1 Features

? Newer products available:

– LMR51430 4.5 to 36-V, 3-A, 500-kHz and 1.1-

MHz synchronous converter

– LM76003 3.5 to 60-V, 3.5-A, 300-kHz to 2.2-

MHz synchronous converter

? For faster time to market:

– TLVM13630 3 to 36-V, 3-A, 200-kHz to 2.2-MHz

power module

? 3.3-V, 5-V, 12-V, 15-V, and adjustable output

versions

? Adjustable version output voltage range,1.23 V to

37 V (57 V for HV version) ±4 maximum over line

and load conditions

? Specified 3-A output current

? Wide input voltage range: 40 V Up to 60 V for HV

version

? Requires only four external components

? 52-kHz fixed-frequency internal oscillator

? TTL-shutdown capability, low-power standby mode

? High efficiency

? Uses readily available standard inductors

? Create a custom design using the LMR33630 or

LM76003 with the WEBENCH? Power Designer

2 Applications

? Motor drives

? Merchant network and server PSU

? Appliances

? Test and measurement equipment

3 Description

The LM2576 series of regulators are monolithic

integrated circuits that provide all the active functions

for a step-down (buck) switching regulator, capable

of driving 3-A load with excellent line and load

regulation. These devices are available in fixed output

voltages of 3.3 V, 5 V, 12 V, 15 V, and an adjustable

output version.

Requiring a minimum number of external

components, these regulators are simple to use

and include fault protection and a fixed-frequency

oscillator.

The LM2576 series offers a high-efficiency

replacement for popular three-terminal linear

regulators. It substantially reduces the size of the heat

sink, and in some cases no heat sink is required.

A standard series of inductors optimized for use

with the LM2576 are available from several different

manufacturers. This feature greatly simplifies the

design of switch-mode power supplies.

Other features include a ±4 tolerance on output

voltage within specified input voltages and output

load conditions, and ±10 on the oscillator frequency.

External shutdown is included, featuring 50-μA

(typical) standby current. The output switch includes

cycle-by-cycle current limiting, as well as thermal

shutdown for full protection under fault conditions.

The LM76003 requires very few external components

and has a pinout designed for simple, optimum PCB

layout for EMI and thermal performance. See the

device comparison table to compare specs.