Power circuits with MIPI RFFE maximize battery life in 2G, 3G, 4G LTE smartphones and tablets

August 27, 2013 // By Paul Buckley
Texas Instruments has introduced the industry's first RF power converters to integrate the MIPI Alliance's radio frequency front-end (RFFE) digital control interface, a specification that simplifies multi-band and multi-radio communications.

The efficient LM3263 buck converter and LM3279 buck-boost converter reduce the heat and power consumption in RF power amplifiers, improving battery life and extending talk time in 2G, 3G and 4G LTE smartphones, tablets and data cards.

The LM3263 2.5-A buck converter's  average power tracking feature helps it meet stringent RF requirements of multi-mode, multi-band power amplifiers with fast output voltage transients. The device also includes active current assist and bypass to minimize inductor size without loss of output regulation -resulting in a 10-mm2 solution, which is half the size of competing solutions. The LM3279 1-A buck-boost regulator supports fast output voltage transients for 3G and 4G LTE. The device enables the amplifier to support high output power and high data rates, even at low battery voltages.

The MIPI RFFE digital control interface provides compatibility with next-generation RF front end chipsets, power amplifiers and reference platforms. The 2.5-A LM3263 meets voltage and current requirements of 2G, 3G and 4G, and the LM3279 supports 1-A loads for 3G and 4G.

The 2.7-MHz LM3263 buck converter results in a 10-mm2 total solution size; and the LM3279 is a 13-mm2 solution.
    
The device's 95-percent efficiency reduces heat dissipation and cuts battery current consumption through average power tracking with dynamically adjustable output voltage.

Designed to meet RF and 3GPP requirements, the LM3279 buck-boost supports high linearity and high output power, even at low battery voltages.

TI also introduced the LM8335 general output expander with MIPI RFFE host interface to complement the LM3263 and LM3279. The expander reduces the general-purpose input/output pin allocation and gives designers greater design flexibility to support up to eight additional analog outputs that use analog-controlled, non-MIPI RFFE compliant components.

Designers can test power and performance with the LM3263, LM3279 and LM8335 evaluation modules for 3G and 4G RF power amplifiers. The modules include all essential active and passive components to compare analog and RFFE digital control modes of