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a

ADP3401

One Technology Way, P.O. Box 9106, Norwood, MA 02062-9106, U.S.A.

Tel: 781/329-4700

World Wide Web Site: http://www.analog.com

Fax: 781/326-8703

© Analog Devices, Inc., 2000

FEATURES

Handles all GSM Baseband Power Management

Functions

Four LDOs Optimized for Specific GSM Subsystems

Charges Li-Mn Coin Cell for Real-Time Clock

Charge Pump and Logic Level Translators for 3 V and 5 V

GSM SIM Modules

Thermally Enhanced 6.1 mm 28-Lead TSSOP Package

APPLICATIONS

GSM/DCS/PCS Handsets

TeleMatic Systems

ICO/Iridium Terminals

GSM Power Management System

FUNCTIONAL BLOCK DIAGRAM

DIGITAL

LDO

VCC

VRTC

VTCXO

PWRONKEY

ROWX

PWRONIN

RESET

ANALOGON

POWER-UP

SEQUENCING

AND

PROTECTION

LOGIC

ADP3401

VBAT

REFOUT

AGND

VCCA

RESCAP

CHRON

SIMBAT

CAP+

CAP

SIMPROG

SIMON

SIMGND

RESETIN

CLKIN

DATAIO

CHARGE

PUMP

LOGIC LEVEL

TRANSLATION

BUFFER

REF

+

I/O

RST

CLK

VSIM

RTC LDO

XTAL OSC

LDO

ANALOG

LDO

DGND

GENERAL DESCRIPTION

The ADP3401 is a multifunction power management system IC

optimized for GSM cell phones. The wide input voltage range of

3.0 V to 7.0 V makes the ADP3401 ideal for both single cell Li-Ion

and three cell NiMH designs. The current consumption of the

ADP3401 has been optimized for maximum battery life, featuring

a ground current of only 150

µA when the phone is in standby

(digital LDO, and SIM card supply active). An undervoltage lock-

out (UVLO) prevents the startup when there is not enough energy

in the battery. All four integrated LDOs are optimized to power

one of the critical sub-blocks of the phone. Their novel anyCAP™

architecture requires only very small output capacitors for stability,

and the LDOs are insensitive to the capacitors’ equivalent series

resistance (ESR). This makes them stable with any capacitor,

including ceramic (MLCC) types for space-restricted applications.

A step-up converter is implemented to supply both the SIM

module and the level translation circuitry to adapt logic signals

for 3 V and 5 V SIM modules. Sophisticated controls are avail-

able for power-up during battery charging, keypad interface, and

charging of an auxiliary backup battery for the real-time clock.

These allow an easy interface between ADP3401, GSM proces-

sor, charger, and keypad. The 28-lead TSSOP package has been

thermally enhanced to maximize power dissipation capability.

Furthermore, a reset circuit and a thermal shutdown function

have been implemented to support reliable system design.

anyCAP is a trademark of Analog Devices, Inc.