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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 RS7110 use a P‐channel MOSFET
pass transistor, its dropout voltage is a function of drain‐to‐source on‐resistance RDS(ON) multiplied by the load current.
VDROPOUT =VIN −VOUT = RDS (ON ) × IOUT
Application Note
Layout
Copper Area
Thermal Area
Top Side (in2)
Bottom Side (in2)
0
SOT‐223 (θJA,°C/W)
TO‐252 (θJA,°C/W)
a
b
c
d
e
f
g
h
i
0
0
0
140
127
84
125
118
89
92
78
73
106
91
64
89
87
63
64
58
55
0.070
0.310
0.067
0.080
0.080
0.285
0.393
0.500
0.067
0.200
0.600
0.285
0.393
0.500
Top view of the PCB layout in real area.
Bottom view of the PCB layout in real area.
DS‐RS7110‐03 September, 2009
www.Orister.com
ORISTER [ ORISTER CORPORATION ]
