Nonvolatile, I2C-Compatible 64-Position, Digital Potentiometer ...

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AD5258DISPLAY APPLICATIONSCIRCUITRYA special feature of the AD5258 is its unique separation of theVLOGIC and VDD supply pins. The reason for doing this is toprovide greater flexibility in applications that do not alwaysprovide needed supply voltages.In particular, LCD panels often require a VCOM voltage in therange of 3 V to 5 V. The circuit in Figure 45 is the rare exceptionin which a 5 V supply is available to power the digitalpotentiometer.VDD will not affect that node’s bias because it is only on theorder of microamps. VLOGIC is tied to the MCU’s 3.3 V digitalsupply because VLOGIC will draw the 35 mA which is neededwhen writing to the EEPROM. It would be impractical to tryand source 35 mA through the 70 kΩ resistor, therefore, VLOGICis not connected to the same node as VDD.For this reason, VLOGIC and VDD are provided as two separatesupply pins that can either be tied together or treated independently;VLOGIC supplying the logic/EEPROM with power,and VDD biasing up the A, B, and W terminals for addedflexibility.C11µFVCC (~3.3V)MCUR610kΩR510kΩ5VAD5258V DDV LOGICSCLSDAGND14.4VABR170kΩR210kΩWR325kΩ–U1AD8565Figure 45. VCOM Adjustment Application+3.5V < V COM < 4.5V05029-006C11µFVCC (~3.3V)MCUR610kΩSUPPLIES POWERTO BOTH THEMICRO AND THELOGIC SUPPLY OFTHE DIGITAL POTR510kΩAD5258V DDV LOGICSCLSDAGND14.4VABR170kΩR210kΩWR325kΩ–U1AD8565+3.5V < V COM < 4.5VFigure 46. Circuitry When a Separate Supply is Not Available for VDD05029-007In the more common case shown in Figure 46, only analog 14.4 Vand digital logic 3.3 V supplies are available. By placing discreteresistors above and below the digital pot, VDD can now be tappedoff the resistor string itself. Based on the chosen resistor values,the voltage at VDD in this case equals 4.8 V, allowing the wiper tobe safely operated all the way up to 4.8 V. The current draw ofFor a more detailed look at this application, refer to the article,“Simple VCOM Adjustment uses any Logic Supply Voltage” inthe September 30, 2004, issue of EDN magazine.Rev. 0 | Page 20 of 24
AD5258OUTLINE DIMENSIONS3.00 BSC3.00 BSC10 <strong>64</strong>.90 BSC15PIN 10.50 BSC0.950.850.750.150.000.270.17COPLANARITY0.101.10 MAXSEATINGPLANE0.230.088°0°0.800.600.40COMPLIANT TO JEDEC STANDARDS MO-187BAFigure 47. 10-Lead Mini Small Outline Package [MSOP](RM-10)Dimensions shown in millimetersORDERING GUIDEModel RAB (Ω) Temperature Package Description Package Option BrandingAD5258BRMZ1 1 1 k –40°C to +85°C MSOP-10 RM-10 D4KAD5258BRMZ1-R7 1 1 k –40°C to +85°C MSOP-10 RM-10 D4KAD5258BRMZ10 1 10 k –40°C to +85°C MSOP-10 RM-10 D4LAD5258BRMZ10-R7 1 10 k –40°C to +85°C MSOP-10 RM-10 D4LAD5258BRMZ50 1 50 k –40°C to +85°C MSOP-10 RM-10 D4MAD5258BRMZ50-R7 1 50 k –40°C to +85°C MSOP-10 RM-10 D4MAD5258BRMZ100 1 100 k –40°C to +85°C MSOP-10 RM-10 D4NAD5258BRMZ100-R7 1 100 k –40°C to +85°C MSOP-10 RM-10 D4NAD5258EVAL 2 Evaluation Board1Z = Pb-free part.2The evaluation board is shipped with the 10 kΩ RAB resistor option; however, the board is compatible with all available resistor value options.Rev. 0 | Page 21 of 24
Page 1: 查询 AD5258 供应商Nonvolati
Page 4 and 5: AD5258Parameter Symbol Conditions M
Page 6 and 7: AD5258ABSOLUTE MAXIMUM RATINGSTA =
Page 8 and 9: AD5258TYPICAL PERFORMANCE CHARACTER
Page 10 and 11: AD5258250120RHEOSTAT MODE TEMPCO (p
Page 12 and 13: AD52585V/DIV 2V/DIV12V WSCL200ns/DI
Page 14 and 15: AD5258THEORY OF OPERATIONThe AD5258
Page 16 and 17: AD5258I 2 C BYTE FORMATSThe followi
Page 18 and 19: AD5258TOLERANCE READBACK MODESTable
Page 22 and 23: AD5258NOTESRev. 0 | Page 22 of 24
Page 24: AD5258NOTES2 2Purchase of licensed

Nonvolatile, I2C-Compatible 64-Position, Digital Potentiometer ...

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