ADP3405

a 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 Narrow Body 4.4 mm 28-Lead TSSOP Package APPLICATIONS GSM/DCS/PCS Handsets TeleMatic Systems ICO/Iridium Terminals GSM Power Management System ADP3405 FUNCTIONAL BLOCK DIAGRAM VBAT ADP3405 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 ADP3405 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 ADP3405 ideal for both single cell Li-Ion and three cell NiMH designs. The current consumption of the ADP3405 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 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 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 implem...