The AAT2601 from Advanced Analogic Technologies ( http://www.analogictech.com ) is the company’s first power management IC designed for the specific requirements of mid-tier CDMA handsets.
Integrating a single-cell Lithium-ion battery charger, a 300 mA step-down converter, five low dropout (LDO) regulators, a reset function and an I2C interface, the latest addition to AnalogicTech’s rapidly expanding Total Power Management IC product family supplies all the power requirements of next-generation CDMA handsets.
As core currents rise in CDMA chipsets for mid range handset phones, it is essential that designers use more efficient power solutions with dynamic voltage adjustment to maximize system performance.
By bringing together a battery charger, a low-noise 300 mA buck converter to power the baseband core, five LDOs for all critical digital, analog, transmit and receive functions, and an I2C interface to control voltages dynamically, the AAT2601 allows designers of CDMA handsets, including those targeted at the Chinese market, to optimize performance, reduce footprint and drive down cost, according to the company.
The battery charger in the AAT2601 is a dynamic device capable of powering the system while charging the battery. This thermally regulated constant current/constant voltage linear charger combines a pass device, reverse blocking protection, high accuracy current and voltage regulation, charge status and charge termination functions.
Charging current, charge termination current and recharge voltage are programmable via an external resistor or by a standard I2C interface. By using the I2C interface to program output voltages, designers can easily optimize system performance.
The 1.8-V step-down converter delivers an output of 300 mA. A 1.5 MHz switching frequency helps minimize the size of supporting external components while keeping switching losses low. Efficiency is greater than 95%. Turn-on time is a fast 120 µs typical.
To power noise-sensitive circuits, the AAT2601’s five LDOs offer 60 dB Power Supply Rejection Ration (PSRR) and low noise operation. One of the LDOs outputs 300 mA for digital circuit applications. The other four output 150 mA each.
The AAT2601 also integrates two load switches to support dynamic power path/sleep mode operation. Total no-load current when the step-down converter and two LDOs are enabled is only 170 µA. The chip also features both over-current and over-temperature protection
The AAT2601 is qualified across the -40 C to +85º C temperature range. It is available in a 36-pin, 0.8-mm high TQFN package. The device sells for $1.81 in 1K quantities.