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1-1-1 Linear Regulator IC
Application Note
■ Heat dissipation and Reliability
The reliability of an IC is highly dependent on its operating temperature.
Please be sure to apply silicone grease to the IC and to mount it to the
heatsink with a proper mounting torque.
Heatsink design should pay particular attention to ensuring sufficient heat
dissipation capacity.
In addition, please take into account the air convection in operation.
■ Calculating Internal Power Dissipation(PD)
PD is given by the following formula:
PD=IO • [VIN(mean)–VO]
Determine the size of the heatsink according to the relationship between
allowable power dissipation and ambient temperature.
■ Setting DC Input Voltage
The following is the waveform of a DC input voltage.
Input Ripple
When setting the DC input voltage, please follow the instructions below:
●Make VIN(min) ≥ [ (Output voltage) + (Minimum dropout voltage) ]
●Make VIN(max) ≤ DC input voltage shown in the "Absolute Maximum Ratings"
■ Thermal Design
The maximum junction temperature Tj(max) given in the absolute maximum ratings
is specific to each product type and must be strictly observed. Thus, thermal
design must consider the maximum power dissipation PD(max), which varies
by the conditions of use, and the maximum ambient temperature Ta(max).
To simplify thermal design, Ta-PD characteristic graphs are provided herein.
Please observe the following steps for heatsink design:
1. Obtain the maximum ambient temperature Ta(max).
2. Obtain the maximum power dissipation PD(max).
3. Look for the intersection point on the Ta-PD characteristic graph and determine
the size of the heatsink.
Although the heatsink size is now obtained, in actual applications, 10-to-20%
derating factor is generally introduced. Moreover, the heat dissipation capacity
of a heatsink highly depends on how it is mounted. Thus, it is recommended to
measure the heatsink and case temperature in the actual operating environment.
Please refer to the Ta-PD characteristic graphs for respective product types.
VIN (min.)
VIN (mean)
VIN (max.)
■ Mounting Torque
SI-3000B ⎤
⎥
SI-3000C ⎥
SI-3000F ⎥
⎥
SI-3000J ⎥
SI-3000KF ⎥
⎥
SI-3000N ⎥ 0.588 to 0.686 [N•m] ( 6.0 to 7.0 [kgf•cm] )
SI-3000R
⎥
⎥
SI-3000ZF ⎥
⎥
SI-3001N ⎥
SI-3002N ⎥
⎥
SI-3003N ⎦
SI-3000V ⎤ 0.686 to 0.882 [N•m] (7.0 to 9.0 [kgf•cm] )
⎦
■ Recommended Silicone Grease
• Shin-Etsu Chemical Co., Ltd.: G746
• GE Toshiba Silicones Co., Ltd.: YG-6260
• Dow Corning Toray Silicones Co., Ltd.: SC102
Please select proper silicone grease carefully since the oil in some grease
products may penetrate the device and result in an extremely short device
life.
■ Others
• Devices can not be operated in parallel connection aiming for a larger current.
• Diodes for isolation purpose are provided in between input and ground, and
also in between output and ground. They may be broken down if the device
is reverse biased. In this case, please clamp the device with low VF diodes to
protect them.
■ Rectifier Diodes for Power Supplies
To rectify the AC input voltage using rectifier diodes for power supplies,
please use SANKEN rectifier diodes shown in the following list. (Please
use a center-tap or bridge configuration in using stand-alone type diodes.)
Series Name
SI-3000B Series
SI-3000C Series
SI-3000F Series
SI-3000J Series
SI-3000ZD Series
SI-3000KD Series
SI-3000KF Series
SI-3000KM Series
Diodes
AM01Z(Axial Type, VRM:200V, IO:1.0A)
RM2Z(Axial Type,VRM:200V,IO:1.2A)
or RBV-402(Bridge Type, VRM:200V,IO:4.0A)
SFPM-62(Surface-Mount Stand-Alone Type,VRM:200V,IO:1.0A)
RM2Z(Axial Type,VRM:200V,IO:1.2A)
or RBV-402(Bridge Type, VRM:200V,IO:4.0A)
SI-3000KMS Series
SI-3000KS Series
SI-3000HM Series
SI-3000LLSL Series
SI-3000LSA Series
SI-3000LU Series
SI-3000LUS Series
SI-3000N Series
SI-3000R Series
SI-3000V Series
SI-3000ZF Series
SI-3001N Series
SI-3002N Series
SI-3003N Series
SFPM-62(Surface-Mount Stand-Alone Type,VRM:200V,IO:1.0A)
SFPM-52(Surface-Mount Stand-Alone Type,VRM:200V,IO:0.9A)
RM2Z(Axial Type,VRM:200V,IO:1.2A)
or RBV-402(Bridge Type, VRM:200V,Io:4.0A)
IC
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