APL5501 Anpec Electronics Corporation, APL5501 Datasheet - Page 12

• Manufacturer Part Number: APL5501
• Description: Low IQ, Low Dropout 500mA Fixed Voltage Regulator
• Manufacturer: Anpec Electronics Corporation

APL5501/2/3
Thermal Protection
Thermal protection limits total power dissipation in the
device. When the junction temperature exceeds
T
nal to turn off the pass transistor and allows IC to
cool. When the IC’ s junction temperature is down by
10℃, the thermal sensor will turn the pass transistor
on again, resulting in a pulsed output during continu-
ous thermal protection. Thermal protection is designed
to protect the APL5501/2/3 in the event of fault
conditions. For continuous operation, do not exceed
the absolute maximum junction temperature of
T
Operating Region and Power Dis-
sipation
The thermal resistance of the case to circuit board,
and the rate of air flow all control the APL5501/2/3’ s
maximum power dissipation. The power dissipation
across the device is P
mum power dissipation is:
P
where T
junction and ambient air, θ
tance of the package, and θ
tance through the printed circuit board, copper traces,
and other materials to the ambient air.
The GND pin of the APL5501/3 provide an electrical
connection to ground and channeling heat away. If
power dissipation is large, connect the GND pin to
ground using a large pad or ground plane, can im-
prove the problem of over heat of IC.
Copyright
Rev. B.2 - May., 2005
J
J
DMAX
=+150℃, the thermal sensor generates a logic sig-
=+150℃.
= (T
J
-T
J
-T
A
ANPEC Electronics Corp.
is the temperature difference between the
A
) / (θ
JC
D
+ θ
= I
OUT
CA
)
(V
JC
CA
IN
is the thermal resis-
is the thermal resis-
-V
OUT
) and the maxi-
12
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