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.