AP1184 ANACHIP [Anachip Corp], AP1184 Datasheet - Page 6

• Manufacturer Part Number: AP1184
• Description: 4A Ultra Low Dropout Positive Adjustable or Fixed-mode Regulator
• Manufacturer: ANACHIP [Anachip Corp]

4A Ultra Low Dropout Positive Adjustable or Fixed-mode Regulator
Thermal Design
The AP1184-XXX incorporates an internal thermal
shutdown that protects the device when the junction
temperature exceeds the allowable maximum
junction temperature. Although this device can
operate with junction temperatures in the range of
150
sink be chosen such that during maximum
continuous load operation, the junction temperature
is kept below this number. The example below
shows the steps in selecting the proper surface
mount package.
Note: Above table is based on the maximum junction temperature of 135
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Functional Descriptions(Continued)
C, it is recommended that the selected heat
As shown in the above table, any of the two packages will do the job. For low cost applications the SOP7 package is
recommended.
Package
TO263
SOP7
Pad Size-1.4”X1.4”
Copper Area
1.0” X 1.0”
θ
JA
25-45
(
65
o
C/W)
6/11
Max Pd (Ta=25
the following equation:
and the amount of copper board needed.
o
C.
2.4W-4.4W
Assuming, the following conditions:
Vout=2.5V
Vin=3.3V
Vctrl=5V
Iout=2A DC Avg.
Calculate the maximum power dissipation using
Pd=Iout*(Vin-Vout)+(Iout/60)*(Vctrl-Vout)
Pd=2*(3.3-2.5)+(2/60)*(5-2.5)=1.68W
Using table below select the proper package
1.7W
o
C)
Max Pd (Ta=45
2.0W-3.6W
1.4W
AP1184
Rev.1.1 Sep 7, 2004
o
C)