1FEATURES
2• 4.5V to 36V Input Voltage Range
• 3A Output Current, 5.2A Peak Current
• 130 mΩ/110 mΩ Integrated Power MOSFETs
• 94% Peak Efficiency with Synchronous
Rectification
• 1.5% Feedback Voltage Accuracy
• Current Mode Control, Selectable
Compensation
• Resistor Programmed, 1MHz Capable
Oscillator
• Adjustable Output Voltage Down to 0.8V
• Compatible with Pre-biased Loads
• Programmable Soft-start with External
Capacitor
• Precision Enable Pin with Hysteresis
• OVP, UVLO Inputs and PGOOD Output
• Internally Protected with Peak Current Limit,
Thermal Shutdown and Restart
• Accurate Current Limit Minimizes Inductor
Size
• Non-linear Current Mode Slope Compensation
• 20-Pin HTSSOP Exposed Pad Package

APPLICATIONS
• Simple to Design, High Efficiency Point of
Load Tegulation from a 4.5V to 36V Bus
• High Performance DSPs, FPGAs, ASICs and
Microprocessors
• Communications Infrastructure, Automotive

DESCRIPTION
The LM20343 is a full featured synchronous buck
regulator capable of delivering up to 3A of load
current. The current mode control loop is externally
compensated with only two components, offering both
high performance and ease of use. The device is
optimized to work over the input voltage range of
4.5V to 36V making it well suited for high voltage
systems.
The device features internal Over Voltage Protection
(OVP) and Over Current Protection (OCP) circuits for
increased system reliability. A precision Enable pin
and integrated UVLO allows the turn on of the device
to be tightly controlled and sequenced. Startup inrush
currents are limited by both an internally fixed and
externally adjustable soft-start circuit. Fault detection
and supply sequencing are possible with the
integrated power good (PGOOD) circuit.
The frequency of this device can be adjusted from
250 kHz to 1.0 MHz by connecting an external
resistor from the RT pin to ground.
The LM20343 is designed to work well in multi-rail
power supply architectures. The output voltage of the
device can be configured to track a higher voltage rail
using the SS/TRK pin. If the output of the LM20343 is pre-biased at startup it will not sink current to pull the
output low until the internal soft-start ramp exceeds
the voltage at the feedback pin.
The LM20343 is offered in an exposed pad 20-pin
HTSSOP package that can be soldered to the PCB,
eliminating the need for bulky heatsinks.