LM3243

Product Folder Sample & Buy Technical Documents Tools & Software Support & Community LM3243 SNVS782C – OCTOBER 2010 – REVISED AUGUST 2015 LM3243 High-Current Step-Down Converter for 2G, 3G, and 4G RF Power Amplifiers 1 Features 1 Input Voltage Range: 2.7 V to 5.5 V High-Efficiency PFM and PWM Modes With Internal Synchronous Rectification Analog Bypass Function with Low Dropout Resistance (45 mΩ Typical) Dynamically Adjustable Output Voltage: 0.4 V to 3.6 V (Typical) in PFM and PWM Modes Maximum Load Current: 2.5 A in PWM Mode PWM Switching Frequency: 2.7 MHz (Average) Modulated Switching Frequency to Aid Rx Band Compliance Operates From a Single Li-ion Cell (2.7 V to 5.5 V) Current and Thermal Overload Protection ACB Reduces Inductor Requirements and Size Minimum Total Solution Size by Using Small Footprint and Case Size Inductor and Capacitors 2 Applications Cellular Phones Hand-Held Radios RF PC Cards Battery-Powered RF Devices 3 Description The LM3243 is a DC-DC converter optimized for powering multi-mode 2G, 3G, and 4G RF power amplifiers (PAs) from a single Lithium-Ion cell. The LM3243 steps down an input voltage from 2.7 V to 5.5 V to a dynamically adjustable output voltage of 0.4 V to 3.6 V. 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 LM3243 operates in constant frequency PWM mode producing a small and predictable amount of o...