ADP197

Data Sheet

Rev. C | Page 10 of 13

THEORY OF OPERATION

GND

EN

VIN

VOUT

ADP197

ADP197-02

ONLY

CHARGE PUMP

AND SLEW RATE

CONTROL

OVERTEMPERATURE

PROTECTION

Figure 25. Functional Block Diagram

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

internal charge pump. The ADP197 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 pin (EN), which

is capable of interfacing directly with 1.8 V logic signals.

The ADP197 is capable of 3 A of continuous operating current

as long as TJ 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.

The ADP197-02 incorporates a QOD circuit to discharge the

output capacitance when the ADP197-02 output is disabled.

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 EN pin. The package is a space-

saving 1.0 mm × 1.5 mm, 0.5 mm pitch, 6-ball WLCSP and a

tiny 2.0 mm × 2.0 mm × 0.55 mm, 0.65 mm pitch, 6-lead LFCSP.