1 Features

• Functional Safety-Capable

– Documentation available to aid functional safety

system design

• Configured for rugged industrial applications

– 4V to 36V input voltage range

– Withstands up to 50V short VIN transient

– 0.6A/1A continuous output current

– 60ns minimum switching on time

– 1.1MHz fixed switching frequency

– –40°C to 150°C junction temperature range

– 98% maximum duty cycle

– Monotonic start-up with prebiased output

– Short-circuit protection with hiccup mode

– Precision enable

– ±1% tolerance voltage reference

• Small design size and ease of use

– Integrated synchronous rectification

– Internal compensation for ease of use

– SOT-23 package

• Pin-to-pin compatible with the LMR14010A,

LMR50410, and TPS560430

• Various options in pin-to-pin compatible package

– PFM and forced PWM (FPWM) options

2 Applications

• Major appliances

• PLC, DCS, and PAC

• Smart meters

• General purpose wide VIN power supplies

3 Description

The LMR544xx is a wide-VIN, easy-to-use

synchronous buck converter capable of driving up to

1A and 0.6A load current. With a wide input range of

4V to 36V, the device is designed for a wide range of

industrial applications for power conditioning from an

unregulated source.

The LMR544xx operates at 1.1MHz switching

frequency to support use of relatively small inductors

for an optimized design size. The devices have a PFM

version to realize high efficiency at light load and a

FPWM version to achieve constant frequency and

small output voltage ripple over the full load range.

Soft-start and compensation circuits are implemented

internally, which allow the device to be used with

minimal external components.

The device has built-in protection features, such as

cycle-by-cycle current limit, hiccup mode short-circuit

protection, and thermal shutdown in case of excessive

power dissipation.