APL5538 Anpec Electronics Corporation, APL5538 Datasheet - Page 12
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APL5538
Manufacturer Part Number
APL5538
Description
Dual Channel 300ma Regulator + Reset Ic
Manufacturer
Anpec Electronics Corporation
Datasheet
1.APL5538.pdf
(17 pages)
APL5538
Application Information
Thermal Protection
Thermal protection limits total power dissipation in the
APL5538. When the junction temperature exceeds
T
nal to turn off the pass transistor and let IC to cool.
When the IC’ s junction temperature cools by 10 C,
the thermal sensor will turn the pass transistor on again,
resulting in a pulsed output during continuous thermal
protection. Thermal protection is designed to protect
the IC in the event of fault conditions. For continual
operation, do not exceed the absolute maximum junc-
tion temperature rating of T
Operating Region and Power Dissipation
The thermal resistance of the case and circuit board,
ambient and junction air temperature, and the rate of
air flow all control the APL5538 maximum power
dissipation. The power dissipation across the device
is P = I
is:
P
where T
junction and ambient air.
thermal resistance through the printed circuit board,
copper traces, and other materials to the surrounding
air. The GND pin provides an electrical connection to
ground and channeling heat away. Connect the GND
pin to ground using a large pad or ground plane as a
heat sink, it can improve maximize thermal dissipation.
See figure 1. The SOP-8-P utilizes a bottom thermal
pad to minimize the thermal resistance of the package,
making the package suitable for high current
applications. The thermal pad is soldered to the top
ground pad and is connected to the internal or bottom
ground plane by several vias. The printed circuit board
(PCB) forms a heat sink and dissipates most of the
Copyright
Rev. A.6 - Jul., 2006
JB
J
MAX
=+150 C, the thermal sensor generate a logic sig-
is the thermal resistance of the package,
= (T
OUT
J
-T
J
-T
(V
A
ANPEC Electronics Corp.
A
IN
is the temperature difference between the
) / (
-V
OUT
JB
). The maximum power dissipation
+
BA
)
J
=+150 C.
BA
is the
12
heat into ambient air. The vias are recommended to
have proper size to retain solder, helping heat
conduction.
Ambient
Air
118 mil
Figure 1
SOP-8-P
102 mil
Die
Vias
Thermal
www.anpec.com.tw
pad
Internal
ground
plane
ground
Printed
circuit
board
Top
pad