LM3253

LM3253 www.ti.com SNVS791Q – FEBRUARY 2012 – REVISED MAY 2013 LM3253 High-Current Step-Down Converter for 2G/3G/4G RF Power Amplifiers Check for Samples: LM3253 FEATURES 1 2 High-Efficiency PFM and PWM Modes with Internal Synchronous Rectification Analog Bypass Function with Low Dropout Resistance (45 mΩ typ.) Dynamically Adjustable Output Voltage, 0.4V to 3.6V (typ.), in PFM and PWM modes 3A Maximum Load Current in PWM Mode 2.7MHz (average) PWM Switching Frequency Modulated Switching Frequency to Aid Rx Band Compliance Operates From a Single Li-ion Cell (2.7V to 5.5V) ACB Reduces Inductor Requirements and Size Minimum Total Solution Size by Using Small Footprint and Case Size Inductor and Capacitors 16-bump Thin DSBGA Package Current and Thermal Overload Protection APPLICATIONS USB Datacards Cellular Phones Hand-Held Radios RF PC Cards Battery-Powered RF Devices DESCRIPTION The LM3253 is a DC-DC converter optimized for powering multi-mode 2G/3G/4G RF power amplifiers (PAs) from a single Lithium-Ion cell. The LM3253 steps down an input voltage from 2.7V to 5.5V to a dynamically adjustable output voltage of 0.4V to 3.6V. The output voltage is set through a VCON analog input that adjusts the output voltage to ensure efficient operation at all power levels of the RF PA. The LM3253 is optimized for USB datacard applications. The LM3253 operates in constant frequency Pulse Width Modulation (PWM) mode producing a small and predictable amount of o...