1-1-3 Multi-Output Type Regulator ICs
Application Note
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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.
The reliability of discrete components such as capacitors and coils is
closely related to temperature. A high operating temperature may reduce
the service life. Exceeding the allowable temperature may burn the coils or
damage capacitors. It is important to make sure that the temperature of
output smoothing coils and input/output capacitors do not exceed their
allowable levels during operation. With an adequate derating for the coils,
minimize heat emission as far as possible. (For discrete components, refer
to the individual user manuals.)
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Mounting Torque
STA800M Series (when mounted by using a spring)
0.588 to 0.784 [N•m] (6.0 to 8.0 [kgf•cm]
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Recommended Silicone Grease
• Shin-Etsu Chemical Co., Ltd.: G746
• GE Toshiba Silicones Co., Ltd.: YG-6260
• Dow Corning Toray Silicone 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 de-
vice life.
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Thermal Design
The maximum junction temperature T
j(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
P
D(max)
, which varies by the conditions of use, and the maximum ambient
temperature T
a(max)
.
To simplify the thermal design, T
a
-P
D
characteristic graphs are provided
herein. Please observe the following steps for heatsink design:
1. Obtain the maximum ambient temperature T
a(max)
.
2. Obtain the maximum power dissipation P
D(max)
.
3. Look for the intersection point on the T
a
-P
D
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 or case temperature in the actual
operating environment.
Please refer to the T
a
-P
D
characteristic graphs for respective product
types.
ICs
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