1FEATURES
2• Operates From a Single Li-Ion Cell: 2.7V to
5.5V
• Adjustable Output Voltage: 0.6V to 4.2V
• 1A Maximum Load Capability for VIN ≥ 3.2V,
VOUT = 3.6V
• 2.4 MHz (typ.) Switching Frequency
• Seamless Buck-Boost Mode Transition
• Fast Output Voltage Transition: 0.8V to 4.0V in
20 μs
• High-Efficiency: 95% typ. at 3.7 VIN, 3.5 VOUT, at
300 mA
• Cycle-by-cycle Over-Current Limit
• Output Over-Voltage Clamp
• Internal Compensation
• 12-bump DSBGA Package

APPLICATIONS
• Battery-Powered 3G/4G RF PAs
• Cellular Phones
• Portable Hard Disk Drives
• PDAs

DESCRIPTION
The LM3209-G3 is buck-boost DC/DC converter
designed to generate output voltages above or below
a given input voltage. It is particularly suitable for single-cell Li-ion batteries for portable applications.
The LM3209-G3 operates at a 2.4 MHz typical
switching frequency in full synchronous operation
providing seamless transitions between buck and
boost operating modes.
The power converter topology needs only one
external inductor and two capacitors. Five internal
power switches enable high overall efficiency.
The LM3209-G3 is internally compensated for buck
and boost modes of operation, thus providing an
optimal transient response.
The LM3209-G3 is available in an 12-bump lead-free
DSBGA package of size 2.0 mm x 2.5 mm x 0.6 mm.