ON-Display™

QUARTERLY TECHNOLOGY AND APPLICATIONS MAGAZINEFIRST QUARTER 2001Vol. 2, No. 1ON-Display This Quarter...FEATURESA Look at Where We Are 3Power Supply Design Software 29POWER MANAGEMENTWorld’s First Single-Cell Battery PoweredOperational Amplifiers 4Zener Transient Voltage Suppressor (TVS)Delivers Maximum Protection in theMicro POWERMITE® Package 7Ultra-Low Noise LDO Regulators forWireless Applications 8Zener Diode Based Discrete IntegrationFilters, An Alternative to Traditional I/OEMI Filter Devices 10Constant Current PFM Boost Regulatorwith Enhanced Efficiency Operation 12Bipolar Power Transistors Provide NewOptions in Charging and Power Management 15SPICE Models Dramatically ImproveTime-to-Market Figures 17Multi-Phase PWM Controllers ProvideHigh Performance 22New Rectifiers Optimized for Power Supplies 24Additional Zener SOD-323 Voltages 25High Switching Frequency Buck Controllers 25Micropower PWM Step-Up DC-DC Converter 26Micropower Low Dropout RegulatorsUsing NOCAP Technology 28BROADBAND SOLUTIONS3.3V/5V ECL Differential Receiver/Driver with Variable Output Swing 21ON SEMICONDUCTORCOMMITTED TO WIRELESS AND PORTABLESEMICONDUCTOR LEADERSHIPLeading the Way in Broadband Solutions and Power ManagementMULTI-MARKETTiny 6-Pin Device Forms Tiny RC Oscillator 38TO ORDER LITERATURELDC Information 39© 2001, SCILLC

2 • ON-Display ON SEMICONDUCTOR 1Q-2001Go. With the broadest portfolio of power management IC solutions.Go. With the annual producer of more than 19 billion automotive semiconductors.Go. With a supplier that meets the challenging demands of theautomotive industry. Go. Toward the future. Go. With ON Semiconductor.ON Semiconductor www.onsemi.comON-Display is published by ON Semiconductor. All information contained herein is subject to change without notice. Devices and information on devices, includingparameters, are subject to change or discontinuance without notice. Information contained herein may be reproduced by ON Semiconductor Sales and QualifiedDistributors for the purpose of distribution to customers. All other reproductions are subject to copyright law and restrictions. © 2001 SCILLC, Inc.For additional information, please contact your ON Semiconductor Sales Representative. Comments, corrections and editorials are welcomed. Please contact GaryMalmberg in the Marketing Communications Group at (+1) 602.244.4984 or by email at gary.malmberg@onsemi.com.ON-Display, SWITCHMODE, SMARTMOS, NOCAP and ON-Demand CDROM are trademarks of Semiconductor Components Industries, LLC.PDF and the PDF Logo are registered trademarks of Adobe Systems Incorporated. POWERMITE is a registered trademark of Microsemi Corporation. Micro8 is atrademark of International Rectifier. V 2 is a trademark of Switch Power, Inc. PSpice is a registered trademark of Cadence Design Systems, Inc. Excel is a trademarkof Microsoft Corporation. ChipCenter is a service mark of ChipCenter LLC.All other brand names and product names appearing in this publication are registered trademarks or trademarks of their respective holdersON Semiconductor and the ON logo are trademarks of Semiconductor Components Industries, LLC (SCILLC). SCILLC reserves the right to make changes withoutfurther notice to any products herein. SCILLC makes no warranty, representation or guarantee regarding the suitability of its products for any particular purpose, nordoes SCILLC assume any liability arising out of the application or use of any product or circuit, and specifically disclaims any and all liability, including without limitationspecial, consequential or incidental damages. “Typical” parameters which may be provided in SCILLC data sheets and/or specifications can and do vary in differentapplications and actual performance may vary over time. All operating parameters, including “Typicals” must be validated for each customer application by customer’stechnical experts. SCILLC does not convey any license under its patent rights nor the rights of others. SCILLC products are not designed, intended, or authorizedfor use as components in systems intended for surgical implant into the body, or other applications intended to support or sustain life, or for any other applicationin which the failure of the SCILLC product could create a situation where personal injury or death may occur. Should Buyer purchase or use SCILLC products for anysuch unintended or unauthorized application, Buyer shall indemnify and hold SCILLC and its officers, employees, subsidiaries, affiliates, and distributors harmlessagainst all claims, costs, damages, and expenses, and reasonable attorney fees arising out of, directly or indirectly, any claim of personal injury or death associated withsuch unintended or unauthorized use, even if such claim alleges that SCILLC was negligent regarding the design or manufacture of the part. SCILLC is an EqualOpportunity/Affirmative Action Employer.To order literature on any of these products, see the Literature Distribution Center Information on page 39.

1Q-2001 ON SEMICONDUCTORON-Display • 3From the Editor . . .What an exciting time… The wirelessindustry (like many others) is experiencingrapid growth with increasing technologicaladvances. Maintaining our busy schedulesand staying connected used to require a reamof paper, a pay phone and a stack of “sticky”notes. Today, we can access almost limitlessinformation anywhere we go from the palmof our hands. ON-Display will help you stayahead of the technology wave by providingyou the data needed to make informeddesign decisions. We want to make itpossible for our readers to enable theirdesigns with leading edge products anddesign solutions. I think we are making adifference… Our last edition was distributedto more than 80,000 engineers and designersin multiple languages and our readers’ feedbackcontinues to show that we are movingin the right direction.The electronics industry is currentlyundergoing a significant slow downperiod that began in the fourthquarter of 2000. This softening of sales isdriven by a substantial inventory adjustmentin the entire supply chain, as well as a sense ofuncertainty and lack of confidence in theconsumer segment.At ON Semiconductor, we are experiencinga similar business environment, as are all ofour competitors and everyone else in thesupply chain. Over the last several months,our backlog has weakened, and the visibilitygoing forward is extremely limited. However,we view this as a typical inventory adjustmentcycle that is common in our industry. Wespend a lot of time talking with our customersabout their positioning and firmly believe theslow down will be paced by several factors.The most significant factor is the rate withwhich we burn off the inventory. Ourexpectation is that the second half of the year2001 will be an opportunity for returning tosubstantial growth in the industry.FEATUREON Semiconductor, the publisher ofON-Display magazine, is committed tomaintaining its lead in the power managementand broadband solutions markets.ON Semiconductor’s extensive productoffering, cost efficient manufacturing andmicro-packaging leadership fuel theaggressive growth of these market segments.The company will focus collaborative effortswith customers for new application specificstandard product solutions targeted at valueaddedend market applications.The best way to know if we are accomplishingour goal of providing you withreal-time, ready-to-deliver technology andapplications is to hear from you, our readers.Please take a moment to complete theenclosed card with your comments or dropme a line at gary.malmberg@onsemi.com. bGary Malmberg,Editor-in-ChiefON Semiconductor - A Look at Where We AreSteve Hanson, President and CEOWith regard to our internal operations, weview this period as an important one toaccelerate the transformation of our companyinto a world leader in Power Managementand Broadband.The keys to transformation are ourcontinued investment in research anddevelopment, as well as maintaining themanufacturing capability and capacities thatcontinued on page 4CONTENTSAUTOMOTIVE/TRANSPORTATIONMicropower Low DropoutRegulators Using NOCAPTechnology . . . . . . . . . . . . . . . . . 28NETWORKING & COMPUTING3.3V/5V ECL DifferentialReceiver/ Driver with VariableOutput Swing - MC100EP16VS . . . 21Multi-Phase PWM ControllersProvide High Performance,Yet Cost Effective Solutionsfor CPU VCORE Power . . . . . . . . . 22High Switching FrequencyBuck Regulators . . . . . . . . . . . . . 25WIRELESSWorld’s First Single-CellNiCd, NiMH, or Alkaline BatteryPowered Op Amps fromON Semiconductor. . . . . . . . . . . . . 4Zener Transient VoltageSuppressor DeliversMaximum Protection in theMicro POWERMITE® Package . . . . . 7Ultra-Low Noise LDO Regulatorsfor Wireless Applications . . . . . . . . 8Zener Diode Based DiscreteIntegration Filters, AnAlternative to Traditional I/OEMI Filter Devices . . . . . . . . . . . . 10Constant Current PFM BoostRegulator with EnhancedEfficiency Operation . . . . . . . . . . . 12High Performance BipolarTransistors Provide NewOptions in Charging andPower Management . . . . . . . . . . . 15SPICE Models DramaticallyImprove Time-to-Market Figures . . . 17MULTI-MARKETNew Rectifiers Optimizedfor Power Supplies. . . . . . . . . . . . 24Additional ZenerSOD-323 Voltages . . . . . . . . . . . . 25Micropower PWM Step-UpDC/DC Converter . . . . . . . . . . . . 26Power Supply DesignSoftware - POWER 4-5-6. . . . . . . . 29Tiny 6-Pin Device FormsTiny RC Oscillator . . . . . . . . . . . . 38Literature OrderingHow to Order Technical Literatureand ON-Demand CDROMs . . . . . 39http://onsemi.com

ON SEMICONDUCTOR 1Q-2001WIRELESSA Look atWhere WeAre. . .continued4 • ON-Display To order literature on any of these products, see the Literature Distribution Center Information on page 39.continued from page 3we have established over our firstyear of independence, so that weare poised to respond to the upturnin the market. Current internalactions today are focused onmaking us more cost competitiveby enhancing both the internal andexternal business processes.Our commitment to triple ourR&D investment over the first twoyears of existence is still a flagshipcommitment that we intend tohonor. Demonstration of thatcommitment is the continuedproliferation of new products. Weintroduced 420 new products inthe year 2000 and expect tomaintain the momentum movingforward. We are also investingsubstantially in the creation of ourfuture in manufacturingtechnologies. We have not waveredFEATUREin this commitment and do notintend to do so going forward.ON Semiconductor evolvedfrom a historical past and has beentransformed into a truly customerdriven company. During our initialyear as an independent company,we have transitioned into a highperformance power managementand broadband integratedcompany with well over half of ourbusiness being in these areas.Additionally, the service levelsand on time performance of ourmanufacturing operations havedramatically improved, at a timewhen the majority of the industryhas been on allocation and short ofsupply.Most importantly is ourcommitment to our customersregarding the investment wecontinue to make in employing thetechnical resources that willdifferentiate us from ourcompetitors. This begins with thecontinued rapid expansion of ourdesign and applications resources.Since creating the company, wehave more than tripled our designresources in our focused areas andincreased our applicationsengineering capability by greaterthan 12X. That coupled with theexciting new technologies we arecreating in manufacturing willtruly provide solution for ourcustomer designers. This is alreadyevident in major design wins thecompany has achieved in 2000 andthe first part of 2001.We continue that commitmentof ‘customers will come to us first’because we can solve theirproblems.bSteve Hanson, President and CEOAvailableLiteratureMC33501/DNPFSMC33501/DMC33502/D**CDROM DOWNLOAD HARDCOPY**Dual VersionIt is common knowledge thatsupply voltages are decreasingin all types of systemapplications. When it comes tooperational amplifiers in lowvoltage systems, I am reminded ofthe old adage “everybody talksabout the rain, but nobody doesanything about it.” There havebeen some incrementalimprovements in the supplyvoltages for op amps and productson the market have moved from aminimum of 3.0 volts to 2.5 volts,and even down to 1.8 volts. Untilnow, there have been no significantimprovements in supply voltage.With the introduction of theMC33501SNT1 and theMC33503SNT1 fromON Semiconductor it appearsPOWERMANAGEMENTWorld’s First Single-Cell NiCd, NiMH, or Alkaline BatteryPowered Op Amps from ON Semiconductorsomeone has taken the old adageand finally done something aboutit, so to speak. Designed usingON Semiconductor’sSMARTMOS technology theseop amps are the world’s first andonly that can be powered from asingle NiCd, NiMH, or alkalinebattery cell. They are unique intheir ability to provide such lowrail–to–rail performance on boththe input and output. They operateat 0.9 volts and have guaranteedspecifications at 1 volt. This is thelowest supply voltage operation ofany part on the market. However,we are not alone in singing thepraises of this breakthroughproduct, ChipCenter SM recentlyawarded the MC33501 andMC33503 its coveted “Product ofthe Week” award.There are two main reasons thelow voltage specifications of thisseries are important to designers.The first relates to battery life. If asystem uses components that arenot capable of operating below 2.5volts then the PDA or cell phone,for example, no longer operatewhen the battery voltage fallsbelow 2.5 volts and the user knowshis battery is dead. But is it really?What if you had a system withcomponents that operated down to0.9 V? Now the battery voltage hits2.5 volts and keeps working – allthe way down to 0.9 volts. Ineffect, by using 0.9 volt devices inthe system, we have longeroperating times for the portabledevice. Alternatively, if the runtime at 2.5 volts is acceptable, thecontinued on page 5

1Q-2001 ON SEMICONDUCTORON-Display • 5continued from page 4system designer may choose to use0.9 volt devices and use a smallerbattery, thereby keeping theoperating time the same butmaking the endproduct smaller andperhaps saving onbattery costs. The 0.9volt threshold is alsosignificant because it isthe voltage where asingle nickel-cadmium(NiCd), nickel-metalhydride (NiMH) oralkaline battery isconsidered fullydischarged. Using theMC33501 orMC33503 allows the circuit toconsume the entire battery life.The second major benefit of thisseries is that there are now 0.9 voltcore voltages in DSPs andmicroprocessors whereas the bulkof the market is at 3.3 V it was notso long ago that 5.0 volts weretypical. This trend was referred toearlier. All surroundingcomponents must then supportthese main chipsets, such as a DSP,at whatever voltage they use. Thesedevices must interface with signalsat 0.9 volts so the amplifiers mustalso work in this range. Whensystem voltages are this low, rail-torailoperation is a requirement theMC33501 and MC33503 meeteffectively. Rail-to-rail operationmeans that the output voltagesignal swings such that it almosttouches the positive and negativesupply voltages. A graphicalrepresentation is shown in Figure1. These operational amplifiers’unique ability to provide 1.0 Vrail–to–rail performance to within50 mV of both the input andoutput, is achieved at the input byusing a single pair of depletionmode NMOS devices (DNMOS)to form a differential amplifierPOWERMANAGEMENTwith a very low input current of40 fA (or 0.040 pA). Typical unitygain bandwidth is an impressive3 MHz @ 1.0 V supply. A voltageswing that comes within50 millivolts of a 0-to-5 volt supplyvoltage is not as critical as it iswhen the supply voltage rails rangefrom 0-to-0.9 volts. As shown, the50 millivolts use a much higherpercentage of the 0-to-0.9 voltagerange than when the voltage rangeis 0-to-5 volts. In low voltagesystems, it is important to use asmuch of the voltage range aspossible thereby maximizing thesignal integrity and improving thesignal-to-noise ratio. There is noneed for additional powerregulators to generate highersupply voltages when using theseop amps because they operate on asingle supply voltage.There are two versions of thisamplifier available and both arepackaged in the micro-miniaturesurface mount SOT-23-50.9 Vto7.0 VRail-to-Rail Inputhttp://onsemi.com Figure 1.(TSOP-5). The difference betweenthe two versions is that the locationof the supply voltage pin, V CC ,and the ground pin, V EE , areinterchanged. On the MC33501,pin 2 is V CC and pin5 is V EE . On theMC33503 pin 2 isV EE and pin 5 isV CC . These twooptions match thecommon pin-outstyles currently seenon the market in theTSOP-5 package.Offering the twooptions maximizes theflexibility for designersto drop these op ampsinto and upgradeexisting applications. The TSOP-5package enables high-densitycircuit board designs due to its verysmall form factor and has becomethe industry standard package forsingle low voltage amplifiers.The bandwidth is high enoughto make these amplifiers suitablefor a wide variety of applications.With a typical unity gainbandwidth of 5.0 MHz (at 5.0 voltsupply), the amplifier consumesonly 1.65 milliamps, making theMC33501 and MC33503 verycompetitive in the tradeoff betweenthe drain current and the amplifierspeed. Additionally these devicesprovide an “on demand” basecurrent cancellation amplifier. Thisfeature provides base drive to theoutput power devices, by makingcontinued on page 6Rail-to-Rail OutputMC33501MC33503Op AmpscontinuedFeatures• Low Voltage,Single SupplyOperation• Output VoltageSwings within50mV of BothRails at 1.0V• No PhaseReversal on theOutput for Over-Driven InputSignalsApplications• Interface toDSPs orMicrocontrollers• Low VoltageActive Filters• InstrumentationAmplifiersWIRELESS

6 • ON-Display continued from page 5ON SEMICONDUCTOR 1Q-2001WIRELESSPOWERMANAGEMENTMC33501MC33503Op AmpscontinuedFigure 2. Block Diagram of Single Op Amps MC33501 and MC33503A dual version ofthis op amp isavailable in theMC33502DR2.use of a buffer amplifier to performa voltage–to–current conversion.This is done in direct proportionto the load conditions. This featureallows these amplifiers to consumeonly a few microamps of currentwhen the output stage is in itsquiescent mode.The MC33501 and MC33503provide output current of up to50 mA when required and theoutput is capable of driving600 ohms on transmission line.These op amps also haveimpressive noise performance of30 nV/rtHz (at 1 kHz) which isespecially important in the designof communication products thatare sensitive to any noise injectedinto the system. The input offsetvoltage is trimmed to 0.5 millivoltstypical.It is difficult to find an op ampbetter able to appropriately balancethe tradeoffs of critical electricalcharacteristics and still produce aversatile device. When such adevice is also optimized for lowvoltage operation and put in aminiature package, it is truly one ofa kind. There still doesn’t seem tobe anyone doing anything aboutthe rain, but it appears that thelack of very low voltage op ampshas been addressed in theMC33501 and MC33503. bKent Yancik,Marketing EngineerTo order literature on any of these products, see the Literature Distribution Center Information on page 39.

1Q-2001 ON SEMICONDUCTORON-Display • 7POWER MANAGEMENTZener Transient Voltage Suppressor Delivers MaximumProtection in the Micro POWERMITE ® PackageWIRELESSAs the wireless andcommunication marketscontinue their move to nextgeneration IC’s the need forprotection in power managementdevices becomes even greater. Newmicroprocessors, DSP (DigitalSignal Processors) and memorycomponents are becoming moresensitive due to thinner gate oxidesas they strive to cram moretransistors into less space. With theintroduction of the 1PMT5.0AT3Series from ON Semiconductorthe industry can now protect thesesensitive components from highvoltage and high-energy transientswhile using less than 50% of thepackage height of the SMA orSMB packages in use today. Thetransients these devices see in areassuch as switching power supplies,lightning, ESD (ElectrostaticDischarge), reverse polarization, orconnectors can efficiently beclamped using the 1PMT5.0AT3Series devices. While manyapplications are targeting anintegrated solution for thesemiconductor components used inprotection, there is high cost andapplication complexity thataccompany the solution. The lowprofile and reduced size of this newTVS Zener POWERMITE alongwith the clamping, high surgecapability, low impedance and fastresponse time allows for a costeffective discrete solution right atthe source of the transient.The combination ofON Semiconductor’s industryleading Zener technology with thesuperior micro POWERMITEpackage will enable the customer touse one of the lowest height profileFigure 1. POWERMITE versus SMA(1.1 mm), and highest power perboard space devices in the industry.The unique design of thePOWERMITE package deliversthermal resistance and powerdissipation results better than thosefound in the SMA package (seeFigure 1 and Table 1) whileoccupying 41% less board space.With typical applications such asGSM hand sets, battery charger,laptop computers, pagers, palmpilots, and PCMCIA cards, powerper board space is key. These new6.2 V to 47 V Zeners and 5 V tocontinued on page 8AvailableLiterature1PMT5.0AT3/D1PMT5920BT3/DMBRM120ET3/DMBRM120LT3/DMBRM130LT3/DMBRM140T3/DAN784/DAN843/DCDROM DOWNLOAD HARDCOPYMin Footprint 2One Inch Pad 3 Dimensions 5PackageSOD-123POWERMITESMASMBPower Dissipation 2per Board Area 4(W/mm 2 )0.0400.0480.0290.022PD(max) 2(Watts)0.300.500.500.55RΘja(°C/W)429248250226Power Dissipation 3per Board Area 4(W/mm 2 )0.0800.1450.0830.064PD(max) 3(Watts)0.601.501.451.60RΘja(°C/W)206808675Board Contact Area 1(mm 2 )0.705.524.965.36Length(mm)3.853.905.595.59Width(mm)1.802.052.923.81Height(mm)1.351.152.672.41Board Area 4(mm 2 )7.510.317.525.11. Board Contact Area calculated using maximum dimension tolerances.2. Steady state, mounted on FR-4 printed circuit board with 1 oz. copper using minimum recommended footprint. Time = 10 seconds.3. Steady state, mounted on FR-4 printed circuit board with 1 oz. copper using 1.0-in x 1.0-in (25.4-mm x 25.4-mm) printed circuit board (increasedcopper are for heat sinking). Time = 10 seconds.4. Board Area calculated using maximum package dimensions and recommended solder pad size.5. Values are maximum dimensions.AlsoAvailable inSoftcopyBRD8009/DTable 1. Key Features of Surface Mount Packageshttp://onsemi.com CDROMDOWNLOAD

8 • ON-Display POWER MANAGEMENTON SEMICONDUCTOR 1Q-2001WIRELESScontinued from page 758 V TVS devices in thePOWERMITE package optimizethis requirement by supplying thesame peak power dissipation of theSMA, 175 watts for TVSprotection, and 0.5 watts steadystatepower dissipation forRegulation. The features andbenefits of the POWERMITEpackage, the new TVS 3.2 wattZeners and the rest of thePOWERMITE Portfolio (Table 2)will help drive future applicationneeds in power management aswell as protecting sensitivecomponents in the broadbandarena.bDavid Culbertson,Principle Staff EngineerPackage DevelopmentZenersSchottkyTVSPOWERMITEZenerscontinuedDevice1PMT5920BT31PMT5921BT31PMT5922BT31PMT5923BT31PMT5924BT31PMT5925BT31PMT5927BT31PMT5929BT31PMT5930BT31PMT5931BT31PMT5933BT31PMT5934BT31PMT5935BT31PMT5936BT31PMT5939BT31PMT5941BT3VZ6.2V @ 60.5mA6.8V @ 55.1mA7.5V @ 50.0mA8.2V @ 45.7mA9.1V @ 41.2mA10V @ 37.5mA12V @ 31.2mA15V @ 25.0mA16V @ 23.4mA18V @ 20.8mA22V @ 17.0mA24V @ 15.6mA27V @ 13.9mA30V @ 12.5mA39V @ 9.6mA47V @ 8.0mADeviceMBRM120ET3MBRM120LT3MBRM130LT3MBRM140T3DeviceUPR5T3UPR10T3UPR15T3UPR20T3UPR30T3UPR40T3Vf(V)0.530.450.380.55VR(V)50100150200300400IR(µA)10400410500Coming in 3Q01 –Ultra Fast RectifiersIR(µA)222255Device1PMT5.0AT31PMT7.0AT31PMT12AT31PMT16AT31PMT18AT31PMT22AT31PMT24AT31PMT26AT31PMT28AT31PMT30AT31PMT33AT31PMT36AT31PMT40AT31PMT48AT31PMT51AT31PMT58AT3VRWM5.0V7.0V12V16V18V22V24V26V28V30V33V36V40V48V51V58VVBR6.70V8.20V14.00V18.75V21.05V25.65V28.10V30.40V32.75V35.05V38.65V42.10V46.75V56.10V59.70V67.80VTable 2. The BiPolar Discrete POWERMITE PortfolioUltra-Low Noise LDO Regulators for Wireless ApplicationsMC33761MC33762MC33765Features• Ultra-Low Noise:150 nV/√Hz @100 Hz,40 µVRMS• Fast ResponseTime from OFF toON: 40 µS Typ.• 1.5% OutputPrecision @ 25°CDesigned using proprietarydesign techniques fromON Semiconductor, theselow dropout regulators are uniquein their ability to provide ultra-lownoise performance. Targeting therapidly growing wirelessapplications, the family supports awide range of noise sensitiveapplications, such as radiocontrolled systems, cell phones,cordless phones, pagers, PDAs,VCOs and RF stages. In addition,the family has numerousapplications for other portabledevices.The MC33761 is a single lowdrop out (LDO) regulatorfeaturing excellent noiseperformances. Due to itsinnovative design, this is a truelow-noise regulator. It typicallyreaches the incredible level of 40microvolts RMS overall noisebetween 100 Hz and 100 kHzwithout the need foran external bypasscapacitor. Housed ina small SOT-23-5(TSOP-5) package,it represents the idealdesigner’s choicewhen space andnoise are at apremium. The absence of anexternal band gap capacitor speedsthe response time to a wake–upsignal which remains within 40 ms(in repetitive mode), pushing theMC33761 as a natural candidate inportable applications.continued on page 9To order literature on any of these products, see the Literature Distribution Center Information on page 39.

1Q-2001 ON SEMICONDUCTORON-Display • 9POWER MANAGEMENTDropoutVoltageChargeOutputWIRELESSInputVoltagePermanentlyEnables the ICWhen ClosedC31 µF MC33761C11 µFOn/OffControl123R1100 kΩ54Main VoltageOutputcontinued from page 8The MC33761 also hosts a novelarchitecture, which preventsexcessive undershoots when theregulator is loaded with fasttransient bursts, as in typicalbursting systems (TDMA, etc.).Finally, with a static lineregulation better than -75 dB, itfilters and isolates the load fromnoise on the input.The MC33762 is the dual LDOversion, offering the same excellentperformance. Packaged in thepopular Micro8, it minimizesboard space and weight. It isavailable with dual 2.5 volt,2.8 volt and 3.0 volt outputs.Other outputs are available byspecial request.The devices contain internalthermal protection that shuts offthe device if the junctiontemperature reaches 125°C.ON/OFFNCGND342On/OffBand GapReferenceFigure 1. Typical Application Schematic for MC33761, the single version.*Current Limit*Antisaturation Protection*Load Transient ImprovementThe MC33765-2.8V containsfive independent low-noise LDOswith separately switched outputsand independent ENABLE pins,all in a TSSOP-16 surface mountpackage. This level of integrationenables designers to greatlyminimize package count, save spaceand reduce the number ofinterconnecting PCB tracks,thereby minimizing strayinductances.Additionally, each voltageregulator of the MC33765 seriesfeatures its own independentENABLE pin plus a commonENABLE pin to shut down thecomplete circuit when not used.The five outputs can beindependently controlled to powerON and OFF the various sectionsof the application. The outputs canalso use very low value decouplingcapacitors (as low as 100 nF)without jeopardizing the regulator’sstability.ThermalShutdownV outFigure 2. Simplified Block Diagram of Each LDO Section.15V inLike the single and dual devices,low noise voltage is also a keyadvantage of the MC33765. Eachof the five outputs exhibit the samenoise voltage of typically 40microvolts RMS @ from 100 Hz to100 kHz. Each output is capable ofsupplying different currents—up to150 mA for output 4. TheMC33765 features a very lowdropout voltage (0.11 V typical @maximum output current), and avery low quiescent current (5 µAmaximum in OFF mode with noload, 130 µA typical in ON modewith no load).ON Semiconductor plansfurther expansion of its ultra-lownoise LDO family in the future. bLarry Hayes,New Product Launch ManagerDeviceSingle LDOsMC33761SNT1-25MC33761SNT1-28MC33761SNT1-30MC33761SNT1-50Dual LDOsMC33762DM-2525MC33762DM-2528MC33762DM-3030Penta LDOsMC33765DTBOutputVoltage2.5 V2.8 V3.0 V5.0 VTwo 2.5 VTwo 2.8 VTwo 3.0 VFive 2.8 VTable 1. Orderable Part NumbersUltra-LowNoise LDOscontinuedAvailableLiteratureMC33761/DMC33762/DMC33765/DPBMC33765/DBRD8016/DSGD504/DCDROM DOWNLOAD HARDCOPYhttp://onsemi.com

10 • ON-Display POWER MANAGEMENTON SEMICONDUCTOR 1Q-2001WIRELESSNZF220TT1NZF220DFT1NZMM7V0T4Zener Diode Based Discrete Integration Filters, AnAlternative to Traditional I/O EMI Filter DevicesElectromagneticCompatibility (EMC) hasbecome a major designconcern for all devices that mustfunction in close proximity toother electronic devices. Thesedevices must be capable ofoperating without interfering withor becoming effected by theoperation of neighboring devices.In addition, most systems areconnected through cables to othersystems causing the I/O interfaceto become a major source andentry point for conducted andradiated ElectromagneticInterference (EMI) andElectrostatic Discharge (ESD).Today’s advanced products arebased on integrated devices that arefaster and smaller and thus aremore susceptible to EMI.Designers are challenged withincreasing complexity, reducingsize and cost, while stayingcompliant with new EMI and ESDstandards.Traditional EMI I/O FilterOptionsThere are several filter devicesavailable to attenuate the noiseentering and exiting an I/O port,EMI DeviceFerrite BeadsFeedthrough Capacitors/Filter ConnectorsAdvantages• Low Cost• Signal Is Filtered Before PCBEntryincluding ferrite beads, feedthroughcapacitors, filterconnectors and Pi or Tee filters.Applications using these devices aregood candidates for theON Semiconductor family of EMIFilters. These traditional filterdevices are compared in Table 1.Pi and Tee FiltersThe two most popular bidirectionallow pass filterconfigurations are Pi (Figure 1) andTee (Figure 2) filters.Pi and Tee filters can beconstructed using discretecomponents, integrated discretecomponents, or Zener diode basedDiscrete Integration (DI) devices.These filters can be constructedDisadvantages• Relatively Large in Size• High Cost• Large in SizeDiscrete RC Filters • Rs Are Smaller Than Ls • ESD Voltage Is NotClampedDiscrete LC FiltersON SemiconductorFamily of RC ZenerBased FiltersV INC1V IN• 2nd Order LPF with -40 dB/Decade Attenuation• Ls Have Low Insertion Loss/Power Dissipation• Low Cost• Small IC Packages• Minimal ParasiticInductances• ESD Voltage Is ClampedTable 1. EMI Filter Device OptionsR1Figure 1. RC Pi FilterR1• Insertion Loss• ESD Voltage Is NotClampedV OUT• Low FrequencyApplications RequireDiscrete Capacitor inParallelfrom either LCs or RCs; however,they only limit the voltage slew rateand will not clamp the ESD inputvoltage, unless a Zener diode isused.Zener Diode DI Filters: AnAlternative to Traditional EMII/O Filter DevicesThe addition of a zener diodeprovides the ESD protection to thebasic Pi or Tee filter. If two zenersare added to the Pi circuit, theESD input voltage is clamped to anon-destructive voltage level that isequal to the zener voltage of thediode.DI filters are now available insmall SMT IC packages to replacethe low pass filters that areimplemented with discretecomponents. These DI zener diodefilters use the capacitance of a zenerdiode to form a resistor/capacitor(RC) low pass filter that is typicallya Pi filter. DI filters reduce thecomponent count and the requiredprinted circuit board space. Zenerdiode DI filters are available inboth Pi and Tee filters and in singleline to array configurations. Inaddition, the integration of thefiltering network in an IC improvesthe frequency responseperformance by minimizing theparasitic impedances that resultfrom the multiple contacts betweenthe components.The demand for cost sensitiveportable products such as cellulartelephones resulted in thedevelopment of discrete integration(DI) filters that are now availableto replace low pass filters that havebeen implemented with discreteresistors, capacitors and diodes.The NZMM7V0T4 multiplechannel filter array, as shown inTo order literature on any of these products, see the Literature Distribution Center Information on page 39.R2C1C2Figure 2. RC Tee FilterV OUTcontinued on page 11

1Q-2001 ON SEMICONDUCTORON-Display • 11Part Number Description PackageNZF220TT1NZF220DFT1Single Channel FilterDual Channel FilterSC-75SC-88ANZMM7V0T4 9-Channel Filter 24-Pin QFN** Very Thin Plastic Profile, Fine Pitch, Quad, Flat, No-Lead Package. Also referredto as LPCC, MLF, and MLP by other industry suppliersTable 2. Family of RC Zener Based Filterscontinued from page 10Figure 3, is the first member ofON Semiconductor’s new family ofIPD EMI filters that includessingle, dual and multiplefilter arrays.POWER MANAGEMENT19The schematics forthe NZF220TT1single channel andthe NZF220DFT1dual channel IPDEMI filters areshown in Figures 4and 5. The zenerdiode based Pi filtersare functionally equivalent to theresistor/capacitor filter shown inFigure 6. The Pi filter circuits areformed by a 100 Ω resistor andtwo zener diodes that have a20212223junction capacitance of 22 pF.In addition to theNZMM7V0T4, NZF220DFT1,and NZF220TT1,ON Semiconductor plans to offerDiscrete Integration devices in awide array of configurations fortransient protection, filter, andregulator applications. bMichael Hoogstra, Jim Lepkowski & MiguelPadilla, Applications Engineering24Zener DiodeBasedIntegrationcontinuedWIRELESS18117NC216315414513612 11 10 9 8 7Figure 3.123Figure 4. NZF220DFT1 DeviceSchematic6412Figure 5. NZF220TT1 DeviceSchematicR1100 Ω3 V IN V OUTC122 pFC222 pFFigure 6. Pi Filter Channel - EquivalentCircuitAvailableLiteratureNZF220DFT1/DNZMM7V0T4/DCDROM DOWNLOAD HARDCOPYhttp://onsemi.com

ON SEMICONDUCTOR 1Q-2001WIRELESS12 • ON-Display POWER MANAGEMENTConstant Current PFM Boost Regulator with EnhancedEfficiency OperationNCP1402Features• Extremely LowStart-Up Voltageof 0.8 V• High Efficiency85% (V in = 2.0 V,V OUT = 3.0 V,70 mA)• Only ThreeExternalComponents AreRequiredApplications• Cellular Phones• Pagers• PDA’s• ElectronicGames• Portable Audio -MP3• Camcorders• Digital CamerasThe circuit described in thisarticle is an enhancedefficiency constant currentPFM-mode (pulse frequencymodulation) boost converterdesigned specifically for a backlightdisplay for a battery poweredhandheld device. The PFMregulator is the NCP1402, thatfeatures an on-chip oscillator, PFMcontroller, PFM comparator, softstart,precision voltage reference,driver and power MOSFET withcurrent limit protection.Additionally, this device has a chipenable feature coupled with verylow quiescent current operationand low voltage operation forextended battery life.The circuit diagram shown inFigure 1 shows the typicalconfiguration of a 50 mA constantcurrent regulator employing theNCP1402SN19T1 (1.9 V). TheNCP1402 device series areavailable in a compact TSOP-5package with several standardvoltages ranging from 1.9 to 5 V.Since the voltage feedback forthis device is 1.9 V, a current senseresistor of 1.9 V/50 mA = 38 ohmsis required to maintain 50 mAthrough the display LEDs. This2.5-4.5 VDCInputShutdownC122 µFL168 µHelement dissipates 95 mW, andadversely affects the overallefficiency of the circuit. Theproposed solution shown inFigure 2 employs two additionalsmall-signal transistors to decreasethe sensing circuit powerdissipation to below 20 mW.The required sense resistor isreduced to 3 ohms, dissipating amere 7.5 mW at 50 mA currentregulation. The circuit indirectlyregulates the current across the3 ohm sense resistor by keeping thevoltage across this element toapproximately 150 mV. Since theactual regulation point of theconverter is the 1.9 V-feedback pin(OUT) to the NCP1402, the PNPtransistor provides a low currentbias to this pin and thecomplementary NPN transistor.The NPN transistor is configuredas a common-emitter with thecurrent sense resistor, which isbiased from a low loss resistordividernetwork from the1.9 V-regulation point. The resistordivider is chosen to step down the1.9 V-feedback pin voltage toapproximately a V be drop above150 mV. The transistor pair formsan SCR structure that ensurescorrect biasing conditions for theD1MBRM120ET3C10.1 µFLEDArrayNCP1402SN19T151LXCE OUT 2 50 mAGND4Figure 1. Constant Current PFM Boost Converter1.9 VR638.3 ΩC247 µFindirect output current regulationscheme. This co-packagedcomplementary pair is formedusing the BC848BPDW1T1,which is in a space saving six-pinSOT-363 (SC-88) package.The plot in Figure 3 shows theefficiency improvement affordedwith this technique over theconventional approach.The enhanced current regulationscheme affords an improvement ofover 20% in efficiency, whichtranslates, to a reduction in powerdissipation and longer battery life.This converter was designed tooperate in discontinuous modewith an input voltage range of2.5 V to 4.5 V, providing arelatively constant current of50 mA to a LED array having avoltage drop of approximately5 V. The output power of thisconverter is 250 mW. Neglectingany losses in the power train withthe circuit shown in Figure 1, themaximum achievable efficiency isless than 73%. The additionalcomponents and reduction ofcurrent sense resistor value for theenhanced circuit yields a maximumefficiency neglecting power trainlosses to 93%.The switching frequency of thisconverter is derived by solving therespective time components of agiven switching period, namely theswitch on (t on ) and off-times (t off )and the output current (I O ) interms of fundamental circuitparameters. The NCP1402 seriesoperate with a nominal fixed ontime(t on ) of 5.5-microseconds.Ideally, a boost-converter operatingin either continuous orcontinued on page 13To order literature on any of these products, see the Literature Distribution Center Information on page 39.

1Q-2001 ON SEMICONDUCTORON-Display • 132.5-4.5 VDCInputShutdownC122 µFL168 µHPOWER MANAGEMENTD1MBRM120ET3NCP1402SN19T15LXCE OUT 21GND4R71 kΩQ2ABC848BDW1T1R4100 kΩR8100 Ω1.9 VLEDArray50 mAR5100 ΩC247 µFQ2BBC848BDW1T1WIRELESSR4100 kΩR91 MΩC10.1 µF0.15 VR63 ΩPFM BoostRegulatorcontinuedFigure 2. Enhanced Constant Current PFM Boost ConverterEfficiency (%)85.0080.0075.0070.00Enhanced CurrentSense Circuitcontinued from page 12discontinuous conduction modemaintains the followingrelationship between the on time(t on ), off time (t off ), input (V in )and output voltage (V O ) in steadystateoperation.V in =VO(ton + toff)toff(EQ1)65.00Original CircuitSolving for the off-time yields,60.001.5 2.0 2.5 3.0 3.5 4.0 4.5Input Voltage (VDC)Figure 3. Performance ComparisontONIpktDIOtOFFFigure 4. Idealized Output Diode Current Waveformtoff =Vin • tonV O - Vin(EQ2)Since this circuit indirectlyregulates the current through thedisplay LEDs, we can assume aconstant output current (I O ) of50 mA. The output current isactually the average currentthrough the boost diode (D1)during a switching cycle. Anidealized diode current waveform isshown in Figure 4, where t D is thedead time, I pk is the peak switchcurrent, and t ON and t OFF are theswitch on-time and off-time,respectively.continued on page 14AvailableLiteratureNCP1402/DNPFSNCP1402/DBRD8016/DSGD504/DCDROM DOWNLOAD HARDCOPYhttp://onsemi.com

14 • ON-Display IO = •ON SEMICONDUCTOR 1Q-2001WIRELESScontinued from page 13An equation relating thiswaveform to the output current interms of fundamental circuitparameters is shown with thefollowing expression, which issimply derived by taking the areaof the current waveform divided bythe switch period.POWER MANAGEMENTFinally, to ensure discontinuouscurrent mode operation, the deadtime must be greater than zerothroughout the operating range.The dead time (t D ) is the dwelltime between the switchconduction and time period for theinductor current to fall to zero, asshown in Figure 4. This may becomputed as the differencebetween the switch period, on timeand off time.tD = Ts - ton - toff(EQ6)continued on page 15PFM BoostRegulatorcontinued1TsIpk • toff2(EQ3)Where T s is the switch periodand I pk is the peak inductorcurrent which is given as,Ipk =Vin • tonL(EQ4)Solving for the switch period(T s ) in Equation 3, andsubstituting the expressions for theswitch off-time (t off ) and peakcurrent (I pk ) yields,(Vin • ton) 2Ts = 2 • L • I O • (VO - Vin)fs (V in , V O ) m120108968472604836241202.5 3.0 3.5 4.0 4.5V inFigure 5. Theoretical Switching Frequencies (kHz) versusInput Voltage (VDC)(EQ5)The plot in Figure 5 shows thetheoretical switching frequency(f s = 1/T s ) versus input voltage, fora converter with L = 68 µH,V O ~5 V and an output current(I O ) of 50 mA.The converter operates over afrequency range of approximately9 to 120 kHz. Since the inductorvalue is the only flexible designparameter in this example, it waschosen to keep the peak currentthrough the NCP1402 withinspecified limits, and maintaindiscontinuous-mode operation.The theoretical peak inductorcurrent is shown inFigure 6.I pk (V in )0.400.350.300.250.202.5 3.0 3.5 4.0 4.5V inFigure 6. Calculated Peak Switch and Inductor Current (ADC)versus Input Voltage (VDC)To order literature on any of these products, see the Literature Distribution Center Information on page 39.

1Q-2001 ON SEMICONDUCTORON-Display • 15td (V in , V O )8072645648403224168POWER MANAGEMENT02.5 3.0 3.5 4.0 4.5V inFigure 7. Dead-Time (µsec) versus Input Voltage (VDC)continued from page 14The plot of the theoretical deadtime over the operating inputvoltage range for this circuit isshown in Figure 7.The plot of theoretical dead timein Figure 7 shows that theconditions for discontinuous modeoperation are ensured for thenormal operating range of theconverter.The NCP1402 series as depictedin this design example proves to bea very flexible, compact and efficientplatform for this design. bRoland Saint-Pierre,Field Applications EngineerPFM BoostRegulatorcontinuedWIRELESSHigh Performance Bipolar Power Transistors Provide NewOptions in Charging and Power ManagementIn most applications, circuitdesigners are challenged todesign the most cost-effectivesolution without sacrificing systemperformance. For most newdesigners bipolar junctiontransistors (BJTs) are rarelyconsidered as high currentapplication options due to the highbase drive requirements. In lowvoltage portable applications, lowR DS(on) MOSFETs are thecommon choice. Use of very lowR DS(on) devices are applicablewhen systems require it, such as Li-Ion battery packs for cellularphones and notebook computers,and low voltage/ high current DCto-DCregulators. However, ONSemiconductor’s high voltage BJTtechnology can migrate into lowvoltage applications. This family ofdevices can provide a cost-effectivealternative solution to MOSFETsin low voltage platforms. The BJTsand their characteristics are shownin Table 1.Low voltage BJTs are designed toprovide very low saturationvoltage - V CE(sat) , and very highgain. The high gain characteristicallows for simplified base drivecircuitry, and the low V CE(sat)allows for much more efficient useof the device. These high gain lowV CE(sat) BJTs are packaged inTSOP-6, SOT-223 and SO-8surface mount micropackages thatmeet the needs of the portable andwireless markets. Because thetechnology is less costly than theMOSFET-based technology, thedevices provide an alternate morecontinued on page 16BJTsVCEO(sus)Volts Min303030303035DeviceMMDJ3N03BJTR2MMJT9410T1MMBT6589T1MMDJ3P03BJTR2MMJT9435T1MBT35200MT1PolarityNPNNPNPNPPNPPNPPNP0.120 @ 0.8 A0.150 @ 0.8 A0.250 @ 0.5 A0.145 @ 0.8 A0.210 @ 0.8 A0.150 @ 0.8 AMax VCE(sat) Volts Max@ IC Amps0.175 @ 1.0 A0.200 @ 1.2 A0.300 @ 1.0 A0.175 @ 1.2 A0.275 @ 1.2 A0.200 @ 1.2 A0.500 @ 5.0 A0.450 @ 3.0 A0.650 @ 2.0 A0.535 @ 5.0 A0.550 @ 3.0 A0.310 @ 2.0 AIC (cont)Amps Max332332PackageSO-8SOT-223TSOP-6SO-8SOT-223TSOP-6Table 1. Low Voltage Surface Mount BJT Portfoliohttp://onsemi.com

16 • ON-Display ON SEMICONDUCTOR 1Q-2001WIRELESSPOWER MANAGEMENTB+High GainPNP BJT1.2 A+Rb1kB+R1CcV outRtnA1R2V ref-BJT’scontinuedcontinued from page 15cost effective solution in designsthat do not require fast switching.In applications such as low dropout (LDO) linear regulators, thenew devices allow for 0.2 Vdropout voltage with 1 A loadcurrent as shown in Figure 1.Improvements in futuregenerations of low voltage BJTsmay enable even lower V CE(sat)thus reducing the dropout voltagefor the same given collectorcurrent.In addition, most low voltageapplications require that a diode beplaced in series with the MOSFETin order to block the currentflowing through the intrinsicMOSFET body diode. The use ofa BJT allows for removal of theseries diode and provides currentblocking in both directions thusreducing the system powerdissipation and cost due to fewerrequired components (Figure 2).BJTs are well suited for powermanagement applications wherecost is first priority and switchingand ultra low R DS(on) are not themost critical requirements. Sincemost of the portable hand-heldplatforms use 8.4 volts and lower,BJTs provide advantageswith their bi-directionalcapability. These lowleakage, high gain, and lowV CE(sat) , BJTs provide a costeffectivesolution. Figure 3 showsan example using a BJT as a highside switch to control the RFpower amplifier in a wirelessapplication.ConclusionsIn summary, replacingMOSFETs with a low voltage BJTprovides the following additionalB+_ChargerRtn_ChgB+_ChargerRtn_ChgControlControlFigure 1. Low Cost LDO Regulators Using High Gain BJTsPMOSPNPadvantages:Figure 2. Charger Disconnect Switch1. When using a BJT, thedevice will turn-off whenbase drive is removed.MOSFETs require adischarge of the gatesource capacitance to pullup or pull down gatecontrol as required.2. Lower system powerdissipation when used as ahigh side switchcontinued on page 17ReverseBlockingDiodeBattery2.5-8.4 VBattery2.5-8.4 VB+_LoadRtn_LoadB+_LoadRtn_LoadTo order literature on any of these products, see the Literature Distribution Center Information on page 39.

1Q-2001 ON SEMICONDUCTORON-Display • 17BatteryRtnPAControlA1POWER MANAGEMENTHigh GainPNP BJTFeedbackRF INFigure 3. PA Supply Control CircuitPAcontinued from page 163. Inherent current limiting4. Simplicity in circuit designin a low side switchingapplicationWith its lower cost and its bidirectionalblocking capability, themicropackaged TSOP-6, SO-8 andSOT-223 BJTs offer wireless andportable electronics designersanother cost effective solution inthe area of power managementand battery chargers. bDave Hollander,New Product IntroductionBJT’scontinuedWIRELESSSPICE Models Dramatically Improve Time-to-MarketFiguresWithin the wide family ofSWITCHMODEPower Supplies(SMPS), Flyback convertersrepresent the preferred structure foruse in small and medium powerapplications (1-100 W) such aswall adapters, off-line batterychargers, fax machines etc. Due tothe recent introduction of theNCP1200 from ON Semiconductor,the design phase of aFlyback circuit has almost turnedinto child’s play: two passivecomponents plus a MOSFETaround the integrated circuit andyou are all set! Unfortunately, theimpact of the environment on thesystem can be much more difficultto assess: ESRs variations due totemperature cycles, aging of thecapacitors, various types of load,load and line transients, effect ofthe filter stage, electromagneticfilter etc.This article describes how aSPICE simulator can help thedesigner quickly implement his/herconcept and show how it reacts tooutside world constraints. Thismodel brings several benefitsincluding immediate understandingof how the circuit operates andan improved time-to-market cycle.Testing a new componentWhen selecting a newcomponent from the web or from adata book, the expectation is to beable to test it within one week,providing samples are deliveredquickly and a breadboardimmediately works. Unfortunately,experience shows that this idealschedule often drifts because thedelivery is longer than expected orall the components are not readilyavailable (e.g. the transformer) etc.Understanding the needs of betterand smarter design conditions,ON Semiconductor now makesavailable a comprehensive set oftools with its device releases:application notes, design aids,demoboards, product bulletinsand… SPICE models. SPICEmodels allow the engineer toimmediately test a component, e.g.the one selected on the website,and be familiar with it without anysoldering. All that is needed is acomputer, a dedicated SPICEpackage and the good model. Asyou can see, the time previouslylost in waiting the delivery of thesamples can now be used to test thecomponent on the computer andbe familiar with it. Once the actualdevice finally arrives, the finalapplication is tested in a muchshorter time than starting fromscratch: capitalizing on theinformation learned with theSPICE model.What SPICE Model Do I Need?In the arena of SMPS, we canmake the distinction between twokinds of models: switched modelsand averaged models. Switchedmodels are written as if thedesigner is assembling variousblocks together to finally form thecomponent: a latch, an oscillator,continued on page 18SPICEModelshttp://onsemi.com

ON SEMICONDUCTOR 1Q-2001WIRELESSSPICEModelscontinuedcontinued from page 17a driver etc. The result is a virtualdevice that strives to reproduce thetrue behaviour of the siliconversion. As a result, simply add thecomponent normally chosen whenwiring the breadboard: aMOSFET, a transformer, an optocoupleretc. and run thesimulation. Typical simulationtimes vary with the circuitcomplexity and the computer typebut results are usually obtained inless than five minutes… The otherbenefit lies in the ability to observehigh voltages without danger to theuser or verifying a test circuit withno explosion if the concept provesto be wrong: libraries do not burn!On the other hand, convertersare generally designed to deliver aconstant output voltage (or outputcurrent) regardless of theiroperating conditions. To reach thisdesire, most of today’s systemsimplement a feedback loop. Afraction of the monitoredparameter (the voltage or thecurrent) is permanently comparedto a fixed and precise reference viaan error amplifier. If an error exists,the system strives to modify itsinternal parameters (peak currentsetpoint, switching frequency etc.)to stabilize either voltage or currentdepending on the regulating loop.By closing a loop as suggestedbefore, conditions can exist wherethe phase margin degrades andpermanent or transient oscillationstake place. As a result, it is ofabsolute necessity to assess thestability of the converter underdesign. Moreover, the designermust sweep throughout thenumerous parameters than canaffect the power supply along itslifetime and check that instabilityconditions will never occur.Needless to say despite the naturalprocess, drawing frequency plotswith a pencil and paper might takean infinite amount of time to coverall the situations or the way theycombine with each other. AverageSPICE models allow the study offrequency response and draw Bodeplots in a snap-shots since, bydefinition, switching cycles havedisappeared in favor of an averagedbehavior.UniversalInput10R11 WC14.7 µF350VSMD+L1330 µHC24.7 µF350V+1234NCP1200AdjFBCSGndHVNCV CCDrv8765C310 µFM1MTD1N60E+1WSMD18 • ON-Display Figure 1. A Working Offline Solution Describing the NCP1200 in a 3.5 W FlybackPOWER MANAGEMENTPutting the Models to Work:Transient SimulationsFigure 1 shows how to build asimple offline flyback delivering3.5 W. It is apparent the NCP1200represents one of the simplestmarket solutions to build aconverter in a simplified way.Documentation such as design aidsand application notes exist tofurther simplify the task, and areavailable on the ON Semiconductorwebsite at www.onsemi.com.An equivalent simulationtemplate is depicted by Figure 2,depicting how the NCP1200model is wired, exactly as suggestedby the application schematic.Active elements such asMOSFETs and diodes aresimulated through their respectivemodels, also available from ONSemiconductor. The filter input isnot represented in this simulationexample. Final results comparinginformation that may be availablefrom the breadboard versussimulation plots are comparedthroughout Figures 3 and 4. Incontinued on page 20AvailableLiteratureNCP1200/DT1D2MBRA140LT3R42.2C4150 pFIC1SFH615A–2L222 µH6 V @ 600 mA+ +C5C7470 µF 10 µF10 V10 VD35.1 VR6560C5CDROM DOWNLOAD HARDCOPYTo order literature on any of these products, see the Literature Distribution Center Information on page 39.

1Q-2001 ON SEMICONDUCTORON-Display • 19+V input126V adj151234X2NCP1200Fs = 32 kNCP120087655+16POWER MANAGEMENTIprimR5100 m23V CCC VCC10 µFI C = 12.1IStartupDrv13X1XFMRRATIO = -0.08R3200 mL23.5 mH+12 43L580 µH10VDrainX7MTD1N60ER sense2.8V senseIsecIripple1I DrainD1MBR140PC3150 pR4100 mC1470 µFIC = 5.9Vsec16L12.2 µHR154701931X4MOC810118D31N752R1610m17R17300 mC210 µF+Iout32VoutRload13.4SPICEModelscontinuedWIRELESSV FBFigure 2. The SPICE Version of the Application SchematicV drain100 V/divV drain100 V/divV sense500 mV/divV sense500 V/divFigure 3. Simulated Steady-State Drain-Source andSense VoltagesFigure 4. Breadboard Measurements of Drain-Source andSense Signalshttp://onsemi.com

20 • ON-Display ON SEMICONDUCTOR 1Q-2001WIRELESSSPICEModelscontinuedcontinued from page 18comparison the difference in thetwo models is negligible. The maindifference being the time requiredto obtain them: wiring abreadboard can almost take half aday (if nothing smokes during thefirst attempts…) while thesimulation plots were obtained inless than five minutes on a350 MHz computer!Closing the Loop with AveragedModelsAs discussed, stability analysis isthe key to ensure stable and reliablesystem behaviour. Averaged SPICEmodels lend themselves very wellto AC analysis. Figure 5 shows anexample of the NCP1200 averagePOWER MANAGEMENTmodel specifically developed foreasy loop analysis.Again, the components areassembled with their actual values.LoL and CoL open the loop in AC(LoL is huge) but close it in DC(LoL is a short for DC). ACinjection is made through CoL.Putting the probes at various placeson the schematic let the designerobserve the transfer function ofchoice (e.g. V out /V stim orV fb /V stim ). Figure 6 depicts thesimulated results comparable withthat of Figure 7 for a realmeasurement. Simulated results inthis example are obtained in onesecond while real measurementstake at least one hour for anexperimented manipulator.A Real Comprehensive OfferProviding models to work with isone thing. However, wiring themin a real SPICE application cantake a given amount of time. Tofurther boost the design cycle,ON Semiconductor offers readyto-usesimulation templates (suchas presented in Figures 2 and 6)declined in three differentsimulation platforms: Intusoft’sIsSpice4, Candence’s PSpice andSpectrum Software’s Micro-Cap.Just download the templates ofchoice from the website and loadthem into the chosen simulationpackage. It is that simple! Pleasenote that some of the applicationcontinued on page 211201+V in1262.380INCTRL12CoL1 kFNCP1200AveragedLoL1 kHFBOUTGND127X1NCP1200_AvFS = 66 kL = 1.8 mRI = 1.5X1XFMRRATIO = 0.12 4D1MBR340R4100 m12.2out1L122 µF12.27 96Rs10 m12.2out2+I outR17300 mV out12.2Rload1414+V stimAC = 1C1470 µFC210 µFout1out2FB2.381111.85R1547011.110Cf100 nFR upp3.9 kX3TL431132.50R low1 kFigure 5. A Complete AC Analysis Test Fixture with the New NCP1200 Averaged Model in a 10 W AC/DC AdapterTo order literature on any of these products, see the Literature Distribution Center Information on page 39.

1Q-2001 ON SEMICONDUCTORON-Display • 21continued from page 20schematics (e.g. average version)work with most demonstrationversions while more complexsimulations (transient analysis forinstance) require the full release torun.ConclusionThis article demonstrates theeffectiveness and time savings of aSPICE model associated withcomponent selection. As anexample, the new ON SemiconductorNCP1200 represents anideal candidate to quicklyimplement an offline power supply.The time usually needed to designa circuit will be reduced by thecomprehensive set of modelsavailable to designers. Documentationincluding design aids andapplication notes exist to furthersimplify the task, and are availableat the ON Semiconductor websitewww.onsemi.com. bChristophe Basso,Applications Engineering, Toulouse, FrancePOWER MANAGEMENTMag (dB)80.0060.0040.0020.000.00–20.00–40.00–60.00–80.0010 100 1 k 10 k 100 kPhase (deg)180.00135.0090.0045.000.00–45.00–90.00–135.00–180.00Figure 6. A Real Measurement Plot Obtained from a Network AnalyserV FB (°)0V FB (dB)10 dB/div45°/divPm = 90°Figure 7. Same Bode Plot Obtained Through Simulation in One Second...SPICEModelscontinuedNETWORKING/COMPUTINGBROADBANDFeatures• >4GHz BW• Variable Output Swing- Use as a Laser Driver in FOM Applications Upto 6Gb/s Data Rates- Use as a High Speed Variable Gain Amplifier• Very Low Jitter (

22 • ON-Display ON SEMICONDUCTOR 1Q-2001NETWORKING/COMPUTINGCS5302CS5322CS5303Multi-phase Buck Controllerswith Programmable VoltageOutput and Integrated GateDriversWith each succeedinggeneration ofmicroprocessor, there isa trend to lower operating corevoltages and a correspondingdemand for ever-increasing currentlevels. The requirements of theseprocessors create new challenges fordesigners trying to cope with thesestringent power managementrequirements.A new family of world-class fixedfrequency, multi-phase step-downvoltage regulators specificallydesigned to power advanced CPUPOWER MANAGEMENTMulti-Phase PWM Controllers Provide High Performance,Yet Cost Effective Solutions for CPU VCORE Powerapplications is now available fromON Semiconductor. These devicesincorporate all the controlfunctions required to power highperformance processors and highcurrent power supplies. The multiphaseapproach to voltageregulation creates significantadvantages in performance, sizereduction and system cost fordesigners. Through the use ofenhanced V2 architectureON Semiconductor provides thefastest possible transient response,excellent overall regulation and easeof use.A multi-phase approach dividesthe total current output into twoor more individual phases, eachproviding a fraction of the overallcurrent. Each output is phaseshifted accordingly; for example, ina two-phase system, the twooutputs are 180 degrees apart, andin a three-phase system, the threeoutputs are 120 degrees apart.Thus, the multiple converters areconnected in parallel and areswitched on at different times.Each individual phase has its ownpulse width modulated (PWM)output and its own driver stages forits external MOSFETs.With the multi-phase method,the overall current output isachieved with significantreductions in output voltage rippleand input current ripple. Thus,smaller inductors can be used, andcontinued on page 24+12 V300 nH+5.0 VENABLE1.0 µF1.0 µF1.0 µF+600 nH3 ×16SP270M1.0 nF1.0 nF61.9 kFeatures• Enhanced V2Control Method• 4 On-Board GateDrivers• On-Board CurrentSense AmplifiersPWRGDV ID0V ID14.12 k34.8 k12.7 kCOMPV FBV DRPCS1CS2CS REFPWRGDV ID0V ID1V ID2V ID3V ID4I LIMREFCS5322R OSCV CCLV CCL1GATE(L)1GND1GATE(H)1V CCH1LGNDSSV CCL2GATE(L)2GND2GATE(H)2V CCH20.1 µF+8 ×4SP820M12 ×10 µFV OUTV ID2V ID3V ID42.80 k0.1 µF1.0 µF600 nH1.0 k.01 µF.01 µF25.5 k.01 µF25.5 kFigure 1. A two-phase 35 amp controller application using CS5322. For higher currents, up to 60 amps, use the three-phaseCS5303. Note that the gate drivers, either four or six, are integrated into the device to minimize additional component count.To order literature on any of these products, see the Literature Distribution Center Information on page 39.

These days you can useall the power you can get.At ON Semiconductor,the power is onand our productsare delivered on schedule.If you need helpjump-starting your design,give us a call.The Power is ON.ON Semiconductor makes the power management semiconductors that save energyin computers, appliances, consumer electronics, even your cars and trucks. In fact,we’re the “Preferred Supplier” of AC/DC regulators, PFC pre-regulators, DC/DC andlinear regulator integrated circuits. The power is ON and we'll help you save it too.www.onsemi.comSource: Venture Development Group. © 2001, SCILLC. ON Semiconductor and the ON Semiconductor logo are trademarks of SCILLC.

24 • ON-Display ON SEMICONDUCTOR 1Q-2001NETWORKING/COMPUTINGMULTI-MARKETAvailableLiteratureCS5302/DCS5322/DCS5303/DCDROM DOWNLOAD HARDCOPYAvailableLiteratureMBR1545CTP/DMBR2045CTP/DMBR2545CTP/DMBR20100CTP/DMBR20200CTP/DDL151/Dcontinued from page 22the circuit will achieve acorresponding increase in inductorslew rate, with output phases ableto ramp up or down much fasterthan a single large output. Thisapproach also permits aconsiderable reduction in inputand output capacitor requirements,as well as reducing overall solutionsize and cost. Better efficiency isachieved by running lower currentsin the devices leading to lower I2Rlosses. Also, by running lowerswitching frequencies (due tosuperior transient response ofenhanced V2 and taking advantageof multi-phase), the switchinglosses are lower.An additional benefit of thermalmanagement comes from themulti-phase approach, as generatedheat is spread among multiple,smaller components.POWER MANAGEMENTThe proprietary multi-phasearchitecture guarantees balancedload current distribution betweenthe phases by continuallymeasuring and adjusting eachphase. Current sensing andamplifying is on-chip, with currentlimiting for each individual phase.This minimizes stress on thecomponents, as well as improvingefficiency. The two-phase CS5302and CS5322 can provide an outputof 40 amps, and the three-phaseCS5302 can provide 60 amps out.Each multiphase device offerseither a 4-bit or a 5-bit VID(Voltage Identification Code) inputfor programming the outputvoltage. Programming accuracy is1%. Programmable output voltagerange is 1.300 to 1.800 volts forthe CS5302, with a 4-bit input,and 1.075 to 1.850 volts for theCS5322 and CS5303, with 5-bitinput.New Rectifiers Optimized for Power SuppliesMBR1545CTP, MBR2045CTP, MBR2545CTP, MBR20100CTP and MBR2020CTPFeatures• Standard TO-220 package• Two Rectifiers per Package• Guard Ring Protection• 150°C Operating TemperatureBenefits• Allows for Cost EffectiveMigration from Previous(Non-P) Version• Alternative Replacement forCompetitor’s Devices• Less Board SpaceConsumption• Stress Protection• Efficient in ThermallyConstrained ConditionsDevice NumberMBR1545CTPMBR2045CTPMBR2545CTPMBR20100CTPMBR20200CTPApplications• SMPS• Reverse ProtectionPackageTO-220TO-220TO-220TO-220TO-220Voltage45 V45 V45 V100 V200 VTable 1. Orderable DevicesThe CS5302 will operate froman input voltage of 5 volts, whilethe CS5322 and CS5303 willoperate from 5 volts and/or 12volts. The devices can be set for200 kHz to 800 kHz operationwith an external resistor. A PowerGood output with an internaldelay is provided in each device.The CS5302, CS5322 andCS5303 are offered in the industrystandard widebody SOIC-28surface mount package. With theMOSFET gate drivers integratedinto these devices, great savings incomponent count, pcb real estateand system cost are achieved.Fewer components equates toreduced inventory cost, fewermanufacturing steps, and higherquality.bLarry Hayes,Product Launch ManagerAmperes15 A20 A25 A20 A20 AVf @ 25°CRated Specs0.84 V0.84 V0.84 V0.95 V1.0 VCDROM DOWNLOAD HARDCOPYTo order literature on any of these products, see the Literature Distribution Center Information on page 39.

1Q-2001 ON SEMICONDUCTORON-Display • 25Additional Zener SOD-323 VoltagesMM3Z2V4T1 SeriesKey Features• Steady State Power Rating of200 mW• Standoff Voltage from 2.4 Vto 75 V• Small Body OutlineDimensions: 0.067” X 0.049”(1.7 mm X 1.25 mm)High Switching Frequency Buck RegulatorsCS51411, CS51412, CS51413 and CS51414Features• Industry-Leading HighSwitching Frequency• High Accuracy PerformanceOver Entire VIN Range-Basedon VREF regulation as aMeasure of Output Voltage• Low Quiescent Current(100 µA, Typical)• Integrated 1.5 A Power Switchand Dual-FrequencySwitching• Wide VIN Range (+4.5 V to+40 V)• Over-Voltage CircuitProtection and ThermalShutdownPOWER MANAGEMENT• Low Body Height: 0.035”(0.9 mm)• Flammability Rating:UL94 V-0• Voltage regulationBenefits• Saves Cost• Saves Board SpaceBenefits• Reduces Design andProduction Costs:- Lowers Bill of Materials- Requires Fewer and Less-Costly ExternalComponents- Simplifies Board LayoutDesign• Saves System Failures Due toThermal Shutdown andShort-Circuit Protection• SOIC-8 Package EnablesSmaller Form FactorsApplications• Cellular Base Stations• Wireless Infrastructure• High-Speed Data• General Power Supply• Signal SwitchingAvailableLiteratureMM3Z2V4T1/DCDROM DOWNLOAD HARDCOPYCS51411CS51412CS51413CS51414MULTI-MARKET NETWORKING/COMPUTINGD11N41484.5 V – 16 VC2100 µFShutdownSYNCC1U1 210.1 µFV3IN BOOST V SW3.3 VL14SHDNB15 µHCS51411/3R15SYNCD3205 C3100 µF1N5821V C GND V FB8 6 7R2C41270.1 µFAvailableLiteratureCS51411/DNPFSCS51411/DFigure 1. Typical ApplicationCDROM DOWNLOAD HARDCOPYhttp://onsemi.com

26 • ON-Display POWER MANAGEMENTON SEMICONDUCTOR 1Q-2001MULTI-MARKETNCP1400AMicropower PWM Step-Up DC-DC ConverterNCP1400AFeatures• 180 kHz Switching Frequency• High Efficiency (88% atI O = 10 mA)• Low Quiescent Bias Current(23 µA)• Input Voltage (Start-Up)Down to 0.3 V• Input Voltage (OperationHold) Down to 0.9 V• Output Voltage Range from1.8 V to 5.0 V• Low Output Ripple withTypical 15 mV• Output Current up to100 mA at V IN = 3.0 V• Low Profile TSOP-5 PackageBenefits• Space Savings (60% Reductionin Footprint OverMC33466 in SOT-89)• Low Noise• Chip-Enable Feature ReducesCurrent Consumption;Provides Longer Battery Life• One-Cell Battery Operation• Pin-to-Pin Compatible withCompetitive DevicesApplications• Handheld Games• Cellular Phones and Pagers• MP3 Players• PDAs• Camcorders and Digital StillCameras• Handheld InstrumentsFigure 1. Typical Step-Up ConverterV in outApplicationVCELX15OUT2NC3NCP1400AGND4Device NumberNCP1400ASN19T1NCP1400ASN27T1NCP1400ASN30T1NCP1400ASN33T1NCP1400ASN50T1OutputVoltage1.9 V2.7 V3.0 V3.3 V5.0 VSwitchingFrequency180 kHz180 kHz180 kHz180 kHz180 kHzAvailableLiteratureNCP1400A/DNPFSNCP1400/DCDROM DOWNLOAD HARDCOPYTo order literature on any of these products, see the Literature Distribution Center Information on page 39.

High PerformanceOff-Line SMPS Design HasNever Been EasierNCP1200: Solution for Low No-LoadStandby PowerC310 µF400V+1 Adj2 FBHV 8NC 7D21N58196.5 V @ 800 mAC2470 F 10 V3 CS VCC 64 Gnd Drv 5M1MTD1N60ERf470UniversalInputEMIFILTERCS10 µF+NCP 1200R SenseDB5 V1VIN (Vac)90Input Power(with Aux Winding)55 mWInput Power(without Aux Winding)155 mW12024026560 mW75 mW75 mW190 mW355 mW400 mWNo-Load Standby Power Measurement on a 4 W Adapter DesignOutput Power(No Load)0000Key Features• Extremely Low No-Load Standby Power• No Auxiliary Winding Operation• Internal Output Short-Circuit and Open Loop Protection• Current-Mode with Skip Cycle Capability (Adjustable Skip Level)• Internally Fixed Frequency at 40 kHz, 60 kHz, 100 kHz• Direct Optocoupler Connection• Built-In Frequency Jittering for Lower EMI• SPICE Models Available for TRANsient and AC Analysis• Internal Temperature Shutdown• Up to 500 mA Peak Output DriveThe NCP1200 represents the ideal candidate where low cost, partcountand low no-load standby power are key considerations,particularly in travel chargers, AC/DC adapters, PC/monitorauxiliary supplies, DVD/VCD/VCR/Set-top box power supplies, etc.Thanks to its proprietary Very-High Voltage Integrated Circuittechnology, ON Semiconductor’s NCP1200 will please experts aswell as non-experts in the Switch Mode Power Supplies (SMPS)arena.www.onsemi.com

28 • ON-Display ON SEMICONDUCTOR 1Q-2001AUTOMOTIVE/TRANSPORTATIONCS9201CS9202POWER MANAGEMENTMicropower Low Dropout Regulators UsingNOCAP TechnologyCS9201 and CS9202Features• NOCAP TechnologyEliminates External Capacitor• Low Quiescent Current(450 µA Typical @ 100 µALoad)• Low Dropout Voltage(600 mV @ 100 mA LoadCurrent)• 100 mA Output CurrentCapability• High Accuracy Precision 5.0 VOutput (CS9201) or 3.3 VOutput (CS9202)• ±2% Output Error (Max)• Withstands 74 V PeakTransient Voltage• Protected Against ReverseVoltage (-15 V), Over-Voltage,Short Circuit,Over-TemperatureV INOverVoltageShutdownCurrent Source(Circuit Bias)NOCAP Current LimitSense+ – ErrorAmplifierThermalShutdownBandgapReference(1) Contact factory for optional Sense lead.Figure 1. Block DiagramV OUTSense (1)GNDBenefits• Fewer Components Saves Costand Simplifies Board Layout• Space Savings (No ExternalCapacitor and SOIC-8Package)• Stable Output• Extensive Fault ProtectionProvides Robust OperationAvailableLiteratureCS9201/DCS9202/DNPFSCS9201/DApplications• Driver Entertainment andBody & Chassis AutomotiveApplications• Any Slow Switching, SteadyState or Static LoadApplicationsCDROM DOWNLOAD HARDCOPYTo order literature on any of these products, see the Literature Distribution Center Information on page 39.

1Q-2001 ON SEMICONDUCTORON-Display • 29System design tools haverevolutionized many aspectsof design engineering duringthe last several years. Today’sdesigners are tasked with creatingadvanced power systems that mustwork over wide environmentalextremes during worst caseconditions of line and load. Whiledigital design tools have beenavailable to simplify the digitaldesigners task, and in many casesenabled capabilities that previouslyrequired iterative efforts in trialand error construction and benchtesting, comparable power analogsimulation tools were simply notavailable to power supply designersat any price. At least until now. Asa service to the design community,ON Semiconductor is providingtraining and a copy of this superbdesign tool at its SWITCH-MODE power supply seminarseries. In this article we willexplore this tool, and learn how itwill assist any designer tasked withpower supply design regardless ofskill level and experience.The powerful software tool usedin the seminar is called POWER 4-5-6 from Ridley Engineering. Thissoftware provides true cycle-bycycle large signal simulation,feedback control design, and smallsignal analysis in an integratedpackage. This provides thecapability to perform power stagedesign, control loop design andmagnetics design for ninetopologies most commonly used inthe industry. Continuousconduction mode simulation ordiscontinuous mode simulationand analysis are handled by theexpert techniques within thesoftware. This includes the abilityto perform small signal analysis ofthe control system including loopgain and stability analysis inaddition to providing assistanceFEATUREPower Supply Design Software – POWER 4-5-6with two stage input filter designand analysis. To insure reliability ofthe final design power stage, lossand stress analysis are provided.Output files are supplied for Pspiceand general circuit simulations.POWER 4-5-6 uses clearschematic presentation of circuitsand the design environment withimpressive graphics as the interface.This provides robust and rapidoperation and makes it easy to useand learn. On line help is availableif needed. The program quicklyand easily handles experimentation,review and modification cycles toincrease performance andcreativity. The output of theprocess allows coordination withmagnetics suppliers as well ascapacitor selection for criticaldesign parameters such as ESR.This makes interaction with realworld component suppliers muchmore efficient, regardless of skilland experience.An Example Buck RegulatorDesignThe most common powersupply topology is the buckconverter. In this topology, aninput voltage is chopped by aswitch and then filtered. Theswitches are either on or off andtherefore dissipating very littleenergy. Energy is stored in a seriesinductor; it charges and dischargesaround an operating point thatsupports a regulated load voltage(Figure 1). Note that there is nohttp://onsemi.com Figure 1. Buck Regulator Schematicisolation, the input ground isconnected to the output ground. Ifthe switch (Q1) is always on, theoutput will be equal to the inputminus the drop across Q1 and DCresistance of L1. This is theabsolute maximum output voltagethat can be achieved. The circuitoperates in two modes:1. With Q1 on, D1 is off, andL1 is charging.2. With Q1 off, D1 isconducting, and L1 isdischarging.The best way to visualize circuitoperation is to remember that aninductor opposes a change incurrent. If current is flowingthrough L1 and into the load, thenwhen Q1 turns off, the currentmust continue to flow and the onlypossible path for current is throughD1. The output voltage of thecircuit is proportional to the inputvoltage and the duty cycle of Q1’sconduction.For successful operation of abuck regulator design, it isimportant that the output is stablefor all input and load conditions. Ifthe load or input voltage changes,the output should move smoothlyto the new operating point withoutovershoot. It is also important thatthe output change fast enough toavoid significant voltage droop. Ifit appears these requirements arecontradictory, they are. The trick isoptimizing the circuit.continued on page 30SMPSSoftwareMULTI-MARKET

30 • ON-Display ON SEMICONDUCTOR 1Q-2001MULTI-MARKETSMPSSoftwarecontinued from page 29Power Supply Design with theSoftwareFortunately POWER 4-5-6 canassist with this switched modepower supply design and help usdesign the compensation to keepthe power supply stable. To begin,select the “Enter Power Specifications”button and we see thescreen shown in Figure 2.For this example, we define a3.3 V, 13.2 W power supply with18 V ± 20% input. Press “OK” anda menu with a complete selectionof power supply topologies appears(see Figure 3). We’re studying thebuck topology, so click on the“Buck” selection.Figure 2. Power Input and OutputSpecificationsFEATUREA top-level view of the design isshown (see Figure 4).All the elements of Figure 1 arein this block diagram with detailsof the input filter, the PWMcontroller and the compensationcircuit expanded. A click on theinput filter block will display theInput Filter Component screen asseen in Figure 5.Note that POWER 4-5-6 hasfilled in default (nominal) valuesfor capacitor and inductorcharacteristics. Enter in the realvalues (closest standard EIA values)for the components you chooseand the analysis will reflect theseparameters. The only items missingare the requiredON Semiconductor TVS devicesand fuses or circuit breakersnecessary for operating in offlineapplications. Figure 6 (on page 32)shows the transfer function (filteroutput impedance vs. frequencyand attenuation vs. frequencyplots) of the input filter.Figure 7 (on page 32)summarizes the transistor switchstresses. MOSFETs are modeledwith on-resistance only (as shownwith forward drop set to zero),bipolar transistors are modeledwith both on resistance (to reflectbulk resistance of the device) andforward drop (to reflect V ce(sat) ).Like the bipolar transistor, asshown in Figure 8 (on page 32),the diode is modeled as a forwarddrop 0.6 V and bulk resistance.Forward resistance is small for atypical rectifier and depends on thetype used, so the default value is 0.At this point, fill in the particularvalues from the rectifier datasheet,or simply click the “ON” button tobring up a selection of parts fromwhich to choose.Figure 9 (on page 33) shows thecurrent plots for the diode andtransistor switch. When the switchturns on, it quickly sources currentto charge the inductor. When thetransistor is off, the inductor beginsdischarging with the diode closingthe loop.The power supply designer mustchoose the desired control mode.There are two traditional modes ofcontrol: voltage mode and currentmode. A voltage-mode controllergenerates an error voltage from theoutput and a reference andcompares it to the PWM rampvoltage. When the error voltage isless than the ramp, Q1 is turnedoff. This results in proportionalcontrol. The greater the differencebetween the ramp and the output,the longer the duty cycle periodthe power switch is turned on.continued on page 33Figure 3. Power Supply Topology SelectionTo order literature on any of these products, see the Literature Distribution Center Information on page 39.

1Q-2001 ON SEMICONDUCTORON-Display • 31FEATUREMULTI-MARKETSMPSSoftwareFigure 4. Buck Regulator Block DiagramFigure 5. Input Filter Componentshttp://onsemi.com

32 • ON-Display ON SEMICONDUCTOR 1Q-2001MULTI-MARKETFEATURESMPSSoftwareFigure 6. Input Filter Impedance/Attenuation PlotsFigure 7. Transistor Switch StressesFigure 8. Diode Stress SummaryTo order literature on any of these products, see the Literature Distribution Center Information on page 39.

1Q-2001 ON SEMICONDUCTORON-Display • 33FEATUREMULTI-MARKETSMPSSoftwareFigure 9. Diode/Transistor Current Waveformscontinued from page 30Current-mode control sums theswitch current with a compensatingramp signal and compares it tothe error voltage (POWER 4-5-6accomodates both control modes).Figure 10 (on page 34) summarizesthe characteristics of the outputfilter capacitor (C1).Figure 11 (on page 34) showsthe controller parameters includingthe reference voltage; these valuescan be filled in to reflect thecharacteristics of the selected powersupply controller IC.Feedback Compensation DesignPOWER 4-5-6 supports threetypes of compensation networks asshown in Figure 12 (on page 34).The simplest, called Type 1 (onepole), is an integrator circuit thatallows the output to slew tooperating points at a fixed rate.Type 2 compensation adds apole/zero network to speed up theslew rate at lower frequencies withrapid attenuation at higherfrequencies to assure stability. Type3 adds yet another pole/zero pair.Each screen has a handy helpbutton (shown as a “?”) that bringsup background information. Thehelp screen for the FeedbackCompensation Type is shown inFigure 13.The compensation networkcomponent values are entered inthe Feedback CompensationDesign sheet as shown incontinued on page 34http://onsemi.com

34 • ON-Display ON SEMICONDUCTOR 1Q-2001MULTI-MARKETFEATURESMPSSoftwareFigure 10. Output Capacitor CharacteristicsFigure 11. Pulse Width Modulator (PWM) ControllerCharacteristicsFigure 12. Feedback Compensation TypesFigure 13. Feedback Compensation Types Help Screencontinued from page 33Figure 14 (on page 36). Theresulting Bode (gain/phase) plotsfor Type 3 feedback networks areshown in Figure 15 on page 36.The basic rule for good networkstability is to assure that phasemargin exists. Phase margin atcrossover is the value above -180degrees when the gain equals 0 dB.For a low power buck regulatordesign, the inductor mat bepurchased off-the-shelf. To supportthe selection of the inductor (andthe design of magnetics for morespecialized designs), an inductordesign sheet is provided (Figure 16on page 37). This feature is helpfulto solicit the assistance of thesuppliers inductor and or magneticsapplications engineeringprofessionals if needed. Thesoftware provides all the detailedinformation required to deliverwhat is needed for the design. Thephysical and electrical properties ofthe inductor are entered and theinductor values are used in theanalysis of circuit operation(losses, etc.).POWER 4-5-6 can also be usedto design transformers for otherpower supply topologies (includingan isolated buck topology).continued on page 37To order literature on any of these products, see the Literature Distribution Center Information on page 39.

To register, please see the registration form between pages 38 & 39.For additional information visit our website at www.onsemi.com/smps-seminars.Join Dr. Ray Ridley and ON Semiconductor engineers for a unique two-day SMPS Seminar. You’llget in-depth demonstrations of the latest power design techniques and detailed explanation ofreal-life applications. Attendees will also receive Dr. Ridley’s POWER 4-5-6 software at no extracost. Visit our website and register today. It’s an inexpensive way to add to your knowledge.ON Semiconductor

ON SEMICONDUCTOR 1Q-2001MULTI-MARKET36 • ON-Display FEATUREFigure 14. Feedback Compensation DesignSMPSSoftwareFigure 15. Feedback Network Bode (Gain/Phase) PlotsTo order literature on any of these products, see the Literature Distribution Center Information on page 39.

1Q-2001 ON SEMICONDUCTORON-Display • 37continued from page 34Figure 17 illustrates thetransformer design sheet. POWER4-5-6 includes a core library withcommon, commercially availablecore styles and materials. Othercores can be entered to customizethis library, as seen in Figure 18 onpage 38.ConclusionIn conclusion, POWER 4-5-6 isunique in its completeness, speed,FEATUREaccuracy, low cost and ease-of-use.The list price of $995.00 wouldmore than pay for itself in designtime the first time it is used. If youattend the ON SemiconductorSMPS Seminar, POWER 4-5-6 isincluded with two days of trainingfor only $95.00 USD. Anunbelievable bargain. This softwareshould be a standard tool for everydesigner of SWITCHMODEpower supplies. A demo versioncan be downloaded fromhttp://www.ridleyengineering.com.For more information, seewww.onsemi.com/smps-seminarsto register, download a demoversion or preview the seminar viaa webcast demo.bKevin M. Parmenter,Field Applications Engineering Managerand Lonne Mays,Field Applications EngineerSMPSSoftwareMULTI-MARKETFigure 16. Output Inductor DetailsFigure 17. Transformer Core Detailshttp://onsemi.com

38 • ON-Display FEATUREON SEMICONDUCTOR 1Q-2001MULTI-MARKETREFERENCES[1] http://www.ridleyengineering.com[2] ON Semiconductor SMPS PowerSupply Seminar Materials.[3] Ridley Engineering; POWER 4-5-6Help Files.[4] Ridley Engineering; POWER 4-5-6Users Manual.[5] Ken Coffman, Power Supply DesignSoftware.[6] Feedback Loop Stability Analysis,Walter S. Friauf; McGraw-Hill, 1998.SMPSSoftwareFigure 18. Core LibraryAvailableLiteratureNL27WZ04/DCDROM DOWNLOAD HARDCOPYMany times a designrequires a small, lowpower oscillator toprovide a clock signal that does notneed to be particularly accurate,just reliable. Many suppliers offercrystal oscillators, with highaccuracy that cost several dollarseach. This design concept showshow to build a 500 KHz oscillatoroccupying 1/ 2 -in2, and costing lessthan $0.50 each for all thecomponents. The circuit iscomprised of a single 6-pin device(NL27WZ04 from ON Semiconductor),2 resistors and onecapacitor. The NL27WZ04 ispackaged in the micro-miniatureSC88 (SOT-363) package thatMULTI-MARKETTiny 6-Pin Device Forms Tiny RC Oscillatoroccupies only 4.2 mm2. Thenominal operating volts will be 2.3to 5.0 volts and the approximatedevice frequency can be describedas follows:f = 1/(2.2 R1C) HzR 2 > 8 R 1 , C > 50 pfTo operate at 500 KHz, we allowC=75 pf, and R1 to be 12 KΩ, andR2 to be 100 KΩ.Figure 1 shows a simple circuitbased on a new dual gate logic ICthat functions as a 500 KHzOscillator with strong driveoperating at 3.3 volts with a minimumnumber of components. bFred Zlotnick,Applications ManagerV CC2.3 to 5.0 VOSCOut51 6CNL27WZ04A1GNDA2R1R232GNDY1VCCY2Figure 1. Tiny RC Oscillator4To order literature on any of these products, see the Literature Distribution Center Information on page 39.

1Q-2001 ON SEMICONDUCTORON-Display • 39TOOur Customer Service Teamis ready to fulfill yourorders in five languagesfor data sheets, data books, selectorguides, catalogs, brochures, andany other stocked items in print oron your own personalizedON SemiconductorON-Demand CDROM.Dedicated ON SemiconductorCustomer Service Representativesare available from 7:00am to5:00pm MST, Monday throughORDER LITERATUREON Semiconductor’s Global Literature Distribution CenterFriday, as well as during Europeanand Asian local times (see detailsbelow). You may call, fax or emailyour requests to the numbers oremail addresses listed below.You can also order your literatureor CDROMs directly from theonsemi.com website by using thisURL:http://onsemi.com/literatureThis web address will bring youright to the on-line ordering pagewhere you have the option toSearch for a specific document orclick on our CD Library of predefinedON-Demand CDROMs.800-344-3860or303-675-2175PUBLICATION ORDERING INFORMATIONNORTH AMERICA Literature Fulfillment:Literature Distribution Center for ON SemiconductorP.O. Box 5163, Denver, Colorado 80217 USAPhone: 303-675-2175 or 800-344-3860 Toll Free USA/CanadaFax: 303-675-2176 or 800-344-3867 Toll Free USA/CanadaEmail: ONlit@hibbertco.comFax Response Line: 303-675-2167 or 800-344-3810 Toll Free USA/CanadaN. American Technical Support: 800-282-9855 Toll Free USA/CanadaEUROPE: LDC for ON Semiconductor - European SupportGerman Phone: (+1) 303-308-7140 (Mon-Fri 2:30pm to 7:00pm CET)Email: ONlit-german@hibbertco.comFrench Phone: (+1) 303-308-7141 (Mon-Fri 2:00pm to 7:00pm CET)Email: ONlit-french@hibbertco.comEnglish Phone: (+1) 303-308-7142 (Mon-Fri 12:00pm to 5:00pm GMT)Email: ONlit@hibbertco.comEUROPEAN TOLL-FREE ACCESS*: 00-800-4422-3781*Available from Germany, France, Italy, UK, IrelandCENTRAL/SOUTH AMERICA:Spanish Phone: 303-308-7143 (Mon-Fri 8:00am to 5:00pm MST)Email: ONlit-spanish@hibbertco.comToll-Free from Mexico: Dial 01-800-288-2872 for Access -then Dial 866-297-9322ASIA/PACIFIC: LDC for ON Semiconductor - Asia SupportPhone: 1-303-675-2121 (T-F 9:00am to 1:00pm Hong Kong Time)Toll Free from Hong Kong & Singapore:001-800-4422-3781Email: ONlit-asia@hibbertco.comJAPAN: ON Semiconductor, Japan Customer Focus Center4-32-1 Nishi-Gotanda, Shinagawa-ku, Tokyo, Japan 141-0031Phone: 81-3-5740-2700Email: r14525@onsemi.comON Semiconductor Website: http://onsemi.comFor additional information, please contact your local SalesRepresentativeLDC:LiteratureDistributionCenterDocumentOrderingInstructionsThe Literature DistributionCenter for ONSemiconductor is proud toannounce its ON-DemandCDROM technology. Through theonsemi.com/oncdrom URL, youcan select any documents availablein PDF® format and create yourvery own literature CDROM - ondemand. LDC will burn apersonalized ON-DemandCDROM with your name, orderdate and order number printedright on the face of the CDROM.You can also create your owndocument “library”, save it on thewebsite, and have your libraryburned to an ON-DemandCDROM whenever you want!Each time you request a CDROMfrom your personal library, thewebsite retrieves the most up-todatePDF version of the documentsin your library and putsthem on a new CDROM.For people in sales andmarketing, this is a greattool for presenting yourcustomers with their veryown personalizedliterature CDROM. Justcreate a library based onyour customers’ needs orproducts you want to promote, andsend the personalized ON-Demand CDROM directly to yourcustomer.Please visit the website fordetailed instructions and give thisleading-edge technology a try! bby Steve WestGlobal Technical PublicationsManagerON-Demand CDROM Burnerat LDCON-DemandCDROMshttp://onsemi.com

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