8.1 Overview

The LM43600 regulator is an easy to use synchronous step-down DC-DC converter that operates from 3.5 V to 36 V supply voltage. It is capable of delivering up to 0.5 A DC load current with exceptional efficiency and thermal performance in a very small solution size. An extended family is available in 1 A, 2 A, and 3 A load options in pin-to-pin compatible packages.

The LM43600 employs fixed frequency peak current mode control with discontinuous conduction mode (DCM) and pulse frequency modulation (PFM) mode at light load to achieve high efficiency across the load range. The device is internally compensated, which reduces design time, and requires fewer external components. The switching frequency is programmable from 200 kHz to 2.2 MHz by an external resistor, R_T. It defaults at 500 kHz without R_T. The LM43600 is also capable of synchronization to an external clock within the 200 kHz to 2.2 MHz frequency range. The wide switching frequency range allows the device to be optimized to fit small board space at higher frequency, or high efficient power conversion at lower frequency.

Optional features are included for more comprehensive system requirements, including power-good (PGOOD) flag, precision enable, synchronization to external clock, extendable soft-start time, and output voltage tracking. These features provide a flexible and easy to use platform for a wide range of applications. Protection features include over temperature shutdown, V_CC undervoltage lockout (UVLO), cycle-by-cycle current limit, and short-circuit protection with hiccup mode.

The family requires few external components and the pin arrangement was designed for simple, optimum PCB layout. The LM43600 device is available in the HTSSOP / PWP 16 pin leaded package (6.6 mm × 5.1 mm × 1.2 mm) with 0.65-mm lead pitch.