Data Sheet

ADP199

Rev. 0 | 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

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

4Ω

Figure 29. Functional Block Diagram