7.1 Overview

The LM46000 regulator is an easy-to-use synchronous step-down DC/DC converter that operates from 3.5-V to 60-V supply voltage. The device 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 and 2-A load options in pin-to-pin compatible packages.

The LM46000 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. The device defaults at 500 kHz without R_T. The LM46000 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 LM46000 device is available in the 16-pin leaded HTSSOP / PWP package (6.6 mm × 5.1 mm × 1.2 mm) with 0.65-mm lead pitch.