The LM20343 is a 36V, 3A adjustable frequency synchronous buck regulator with 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. By connecting an external resistor from the RT pin to ground, the frequency of this device can be adjusted from 250 kHz to 1.0 MHz. 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 eTSSOP package that can be soldered.
The LM20343 is a full‑featured synchronous buck regulator capable of delivering up to 3 A of load current. It operates over a wide input range of 4.5 V to 36 V and offers high efficiency (up to 94 %) with current‑mode control and selectable compensation. Integrated protection includes over‑voltage, over‑current, UVLO, and thermal shutdown, while a precision enable pin and programmable soft‑start provide tight control.
The device is supplied in a 20‑lead exposed‑pad eTSSOP package. Pin functions such as SS/TRK, EN, RT, and BOOT allow external frequency adjustment (250 kHz‑1 MHz), voltage tracking, and bootstrap operation. Detailed electrical characteristics, absolute maximum ratings, and performance graphs are provided for design reference.
| Input voltage range | 4.5 V to 36 V |
|---|---|
| Output current | 3 A (5.2 A peak) |
| Peak efficiency | 94 % |
| Adjustable switching frequency | 250 kHz to 1 MHz |
| Package | eTSSOP‑20 exposed‑pad |
| Thermal shutdown temperature | 170 °C |
| Enable pin hysteresis | 50 mV |
The regulator operates from 4.5 V up to 36 V.
By connecting an external resistor to the RT pin, the frequency can be adjusted between 250 kHz and 1 MHz.
It includes internal over‑voltage protection (OVP), over‑current protection (OCP), UVLO, and thermal shutdown circuits.
The device can deliver a continuous 3 A output current, with a peak capability of 5.2 A.