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Based on a maximum operating junction temperature 125°C with an ambient of 25°C, the maximum power dissipation will be:
(T
J
−
T
A
) (125
−
25)
P
MAX
=
=
=
0.555W
θ
JC
+ θ
CA
180
Thermal characteristics were measured using a double‐side board with 1”x 2” square inches of copper area connected to the
GND pin for “heat spreading”.
Dropout Voltage
A regulator’s minimum input‐output voltage differential, or dropout voltage, determines the lowest usable supply voltage. In
battery‐powered systems, this will determine the useful end‐of‐life battery voltage. The RS7100 uses a P‐channel MOSFET
pass transistor, its dropout voltage is a function of drain‐to‐source on‐resistance (R
DS(ON)
) multiplied by the load current.
V
DROPOUT
=
V
IN
−
V
OUT
=
R
DS(ON)
×
I
OUT
DS‐RS7100‐14
April, 2010
www.Orister.com