AIC1531 Datasheet, PDF (8/10 Pages) List of Unclassifed Manufacturers – 500mA Dual Linear Regulator with Internal Power Switch

AIC1531
Instead, they rely on the printed-circuit board to
provide the thermal path. When the AIC1531
operates normally, the maximum power dissipation
is
P_D = (V_IN − V_OUT ) × I_OUT = (5 − 3.3) × 0.5 = 0.85W
At the maximum operation temperature, the thermal
resistance seen by the device, or the combination of
all the thermal paths, should be
R_JA
< ^{165 − 85}
0.85
= 94°C/W .
When the device is mounted on a double-sided
printed circuit board, the ground plane is the most
used thermal path. To make sure the thermal
resistance small enough and the shutdown function
work normally, the thermal resistance between
GND pins to GND plane should be as small as
possible by means of adding more vias. And the
GND plane should be at least 1 square centimeters
of copper.
The layout of AIC1531 is shown in Fig.1. In Fig. 2,
the thermal resistance R_JA is 70.36°C/W where the
AIC1531 is mounted on the double-sided PCB and
measured under the forced-air thermal chamber.
Fig.19 The layout of AIC1531
2.6
2.4
2.2
2.0
1.8
1.6
1.4
1.2
1.0
0.8
0
20
40
60
80
100
Ambient Temperature (°C)
Fig.20 The power thermal shutdown dissipation vs. ambient temperature where R_JA is 70.36°C/W in the forced-air thermal
chamber
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