ADP3404 Datasheet | Analog Devices

a Features Handles all GSM Baseband Power Management Functions Four LDOs Optimized for Specific GSM Subsystems Charges Back-Up Capacitor for Real-Time Clock Charge Pump and Logic Level Translators for 3 V and 5 V GSM SIM Modules Narrow Body 4.4 mm 28-Lead TSSOP Package APPLICATIONS GSM/DCS/PCS Handsets Tele Matic Systems ICO/Iridium Terminals GSM Power Management System ADP3404 FUNCTIONAL BLOCK DIAGRAM VBAT DIGITAL LDO VCC RESET PWRONKEY ROWX POWER-UP SEQUENCING AND PROTECTION LOGIC RTC LDO VRTC PWRONIN ANALOGON RESCAP XTAL OSC LDO VTCXO GENERAL DESCRIPTION The ADP3404 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 ADP3404 ideal for both single cell Li-Ion and three cell Ni MH designs. The current consumption of the ADP3404 has been optimized for maximum battery life, featuring a ground current of only 230 µA when the phone is in standby (digital LDO, analog LDO, and SIM card supply active). An undervoltage lockout (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 any CAP® 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 available for power-up during battery charging, keypad interface and charging of an auxiliary back-up capacitor for the real-time clock. These allow an easy interface between ADP3404, GSM processor, charger, and keypad. Furthermore, a reset circuit and a thermal shutdown function have been implemented to support reliable system...