ADP197

Rev. 0 | Page 10 of 16

THEORY OF OPERATION

GND

EN

VIN

VOUT

ADP197

CHARGE PUMP

AND SLEW RATE

CONTROL

OVERTEMPERATURE

PROTECTION

Figure 23. Functional Block Diagram

The ADP197 is a high-side NMOS load switch, controlled by an

internal charge pump. The APD197 is designed to operate with

power supply voltages between 1.8 V and 5.5 V.

An internal charge pump biases the NMOS switch to achieve a

relatively constant, ultralow on resistance of 12 mΩ across the

entire input voltage range. The use of the internal charge pump

also allows for controlled turn-on times. Turning the NMOS switch

on and off is controlled by the enable input, EN, which is capable of

interfacing directly with 1.8 V logic signals.

is less than 70°C. At 85°C, the rated current drops to 2.22 A.

The overtemperature protection circuit activates if the load cur-

rent causes the junction temperature to exceed 125°C. When

this occurs, the overtemperature protection circuitry disables

the output until the junction temperature falls below approximately

110°C, at which point the output is reenabled. If the fault condition

persists, the output cycles off and on until the fault is removed.

ESD protection structures are shown in the block diagram as Zener

diodes.

The ADP197 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 1.0 mm × 1.5 mm, 6-ball WLCSP.