Preliminary Technical Data

ADP2503/ADP2504

ENABLE

The device starts operation with soft start when the EN pin is

brought high. Pulling the EN pin low forces the device into

shutdown, with a typical shutdown current of 0.2 μA.

In this mode, the PMOS power switches are turned off, the

NMOS power switches are turned on, and the control circuitry is

not enabled. For proper operation, the EN pin must be

terminated and must not be left floating.

UNDERVOLTAGE LOCKOUT

The undervoltage lockout circuit prevents the device from oper­

ating incorrectly at low input voltages. It prevents the converter

from turning on the power switches under undefined conditions

must be greater than 2.25 V to enable the converter. During

are disabled until the supply exceeds the UVLO rising threshold.

THERMAL SHUTDOWN

the device goes into thermal shutdown. In this mode, the power

switches are turned off. The device resumes operation when the

junction temperature again falls below 125°C typical.

SHORT CIRCUIT PROTECTION

When the nominal inductor peak current value of 1.5 A is

reached, the ADP2503/ADP2504 first switch off the NMOS2

transistor if it was active. If the current thereafter continues to

increase by an extra amount of 200 mA, the PMOS1 transistor

is also switched off. This operation is reversible when the short

circuit stops. It allows the inductor current ripple to be mini­

even if a high load current is maintained after the short circuit.

Rev. PrB | Page 11 of 16