1 Features

• Functional Safety-Capable

– Documentation available to aid functional safety

system design

• Configured for rugged industrial applications

– 4.5-V to 36-V input voltage range

– 2-A continuous output current

– 70-ns minimum switching on time

– 500-kHz and 1.1-MHz fixed switching frequency

options

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

– 98 maximum duty cycle

– Start-up with prebiased output

– Internal short circuit protection with hiccup

mode

– ±1.5 tolerance voltage reference

– Precision enable

• Small solution size and ease of use

– Integrated synchronous rectification

– Internal compensation for ease of use

– SOT-23 package

• Pin-to-pin compatible with the TPS54202 and

TPS54302

• PFM and forced PWM (FPWM) options available

• Create a custom design using the LMR51420 with

the WEBENCH® Power Designer

2 Applications

• Appliances

• Building automation

• Motor drives

• General purpose wide VIN power supplies

3 Description

The LMR51420 is a wide-VIN, easy-to-use SIMPLE

SWITCHER® synchronous buck converter capable of

driving up to 2-A load current. With a wide input range

of 4.5 V to 36 V, the device is suitable for a wide

range of industrial applications for power conditioning

from an unregulated source.

The LMR51420 operates at 500-kHz and 1.1-MHz

switching frequency to support use of relatively small

inductors for an optimized solution size. The device

has a PFM version to realize high efficiency at

light load and 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 allows the device to be

used with minimum 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. The LMR51420 is available in a

6-pin SOT-23 package.