Texas Instruments LM3243TMX/NOPB

Description
The LM3243 is a DC-DC converter designed for powering multi-mode 2G/3G/4G RF power amplifiers (PAs) from a single Lithium-Ion cell. It steps down an input voltage from 2.7V to 5.5V to an adjustable output voltage of 0.4V to 3.6V. The output voltage is set through a VCON analog input, ensuring 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 output voltage ripple. This enables compliance with ECTEL power requirements in GMSK and EDGE spectral compliance, with minimal filtering and excess headroom. In PFM mode, the LM3243 minimizes DG09 current consumption, maximizing efficiency.
The LM3243 features an Active Current assist and analog Bypass (ACB) to minimize inductor size without compromising output regulation over the entire battery voltage and RF output power range, until dropout. ACB provides a parallel current path to limit the maximum inductor current to 1.4A (typ.) while driving a 2.5A load. It also enables operation with minimal dropout voltage.

Features
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
2.5A Maximum Load Current in PWM Mode
2.7 MHz (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
Cellular Phones
Hand-Held Radios
RF PC Cards
Battery-Powered RF Devices