Datasheet

Data Sheet ADP199
Rev. A | Page 11 of 16
THEORY OF OPERATION
The ADP199 is a high-side NMOS load switch controlled by
an internal charge pump. The ADP199 is designed to operate
with power supply voltages between 0.9 V and 3.6 V.
An internal charge pump biases the NMOS switch to achieve a
relatively constant, ultralow on resistance of 40 mΩ across the
entire input voltage range. The use of the internal charge pump also
allows for controlled turn-on times. The switch is controlled on/off
by the enable (EN) input and is capable of interfacing directly with
1.2 V logic signals.
The ADP199 is capable of 500 mA of continuous load current
as long as T
J
is less than 85°C.
ESD protection structures are shown in the block diagram (see
Figure 29) as Zener diodes.
The ADP199 is a low quiescent current device with a nominal
4 MΩ pull-down resistor on its enable pin (EN). The package is a
space-saving 0.8 mm × 0.8 mm, 4-ball WLCSP.
GND
EN
VIN
VOUT
ADP199
CHARGE PUMP
AND SLEW RATE
CONTROL
09672-029
4MΩ
Figure 29. Functional Block Diagram