GSM Power Management System
Handles all GSM Baseband Power Management
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
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 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 ADP3405, GSM proces-
sor, charger, and keypad. Furthermore, a reset circuit and a
thermal shutdown function have been implemented to support
reliable system design.
FUNCTIONAL BLOCK DIAGRAM
I/O CLK RST
anyCAP is a registered trademark of Analog Devices, Inc.
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use, nor for any infringements of patents or other rights of third parties
which may result from its use. No license is granted by implication or
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