ADP3401

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 mA 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 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 backup battery for the real-time clock. These allow an easy interface between ADP3401, GSM processor, 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.