The LDOs are designed with anyCAP® technology that allows any type of capacitors to be used at the output of the circuit, including small, low-cost ceramic types. The ADP3408 is designed to operate with the AD20msp430 SoftFone, which is comprised of two chips: the AD6521 GSM voiceband/baseband mixed-signal codec, and the AD6522 GSM/GPRS controller. In addition to its low quiescent current operation, the ADP3408 can be controlled by the baseband chipset to enable/disable selected handset functions for optimized power management during different modes of operation.
Single-Chip, Multi-Function Power System
Thu, 02/21/2002 - 5:15am
The ADP3408 is a multi-function power system chip optimized for GSM/DCS/PCS handsets, especially those based on Analog Devices' AD20msp430 system solution. This single chip contains six LDOs, one to power each of the critical GSM sub-blocks. On-board sophisticated controls are user-configurable for power-up during battery charging, keypad interface, and RTC alarm. The charge circuit maintains low current charging during the initial charge phase and provides an end-of-charge signal when a Li-Ion battery is fully charged. Two options of the ADP3408 allow for core LDO output voltages of either 2.5 V or 1.8 V.