Features

(LDO1)

(LDO2)

(LDO4)

for Each LDO

1.

Description

The AT73C239 is a 4-channel Power Supply Power Management Unit (PMU) avail-

able in a QFN 3 x 3 mm package. It is a fully integrated, low cost, combined Power

Management device for wireless modules, GPS and WLAN devices. It integrates four

Linear Low Drop Out (LDO) Regulators, three of which provide high-accuracy RF per-

formance and one (LDO4) with very low quiescent current that is supplied by an

external backup battery. A Low Power Bandgap (LPBG) requiring no external capaci-

tor for decoupling, is used as reference voltage for LDO4 and starts when VBAT is

present. LDO4 regulates output voltage with extremely low quiescent current, maxi-

mizing the lifetime of the backup battery. An Internal State Machine manages the

startup of the other LDOs in the order of LDO3 then LDO1 then LDO2. An economic

High Power Bandgap (HPBG) provides highly accurate, low noise voltage reference

to LDOs 1, 2, 3. HPBG operates in switching mode thereby decreasing its current con-

sumption and becomes inactive when not directly supplied by VIN current. When the

RF LDOs are in idle mode, quiescent current is decreased to a minimum.

The AT73C239 features a Two-wire Interface (TWI) to increase the efficiency of the

system by disabling LDOs when not needed.

Power

Management for

Mobiles (PM)

AT73C239

4-channel Power

Management for

Wireless

Modules

Summary

6201AS–PMAAC–24-Oct-05