SS/ON1

SS/ON2

LM2642

PGOOD1

H

H

L

L

UV_Delay

1.3V-27V

1.3V-27V

4.5V-30V

LM2642

www.ti.com

SNVS203I – MAY 2002 – REVISED APRIL 2013

LM2642 Two-Phase Synchronous Step-Down Switching Controller

Check for Samples: LM2642

1

FEATURES

DESCRIPTION

The

LM2642

consists

of

two

current

mode

2

•

Two Synchronous Buck Regulators

synchronous

buck

regulator

controllers

with

a

•

180° Out of Phase Operation

switching frequency of 300kHz.

•

4.5V to 30V Input Range

The two switching regulator controllers operate 180°

•

Power Good Function Monitors Ch.1

out of phase. This feature reduces the input ripple

•

37µA Shutdown Current

RMS

current,

thereby

significantly

reducing

the

required

input

capacitance.

The

two

switching

•

0.04% (typical) Line and Load Regulation Error

regulator outputs can also be paralleled to operate as

•

Current Mode Control With or Without a Sense

a dual-phase single output regulator.

Resistor

The output of each channel can be independently

•

Independent Enable/Soft-start Pins Allow

Simple Sequential Startup Configuration.

internal 5V rail is also available externally for driving

•

Configurable for Single Output Parallel

bootstrap circuitry.

Operation. (See Figure 3).

Current-mode feedback control assures excellent line

•

Adjustable Cycle-by-Cycle Current Limit

and load regulation and a wide loop bandwidth for

•

Input Under-voltage Lockout

excellent response to fast load transients. Current is

sensed across either the Vds of the top FET or

•

Output Over-voltage Latch Protection

across an external current-sense resistor connected

•

Output Under-voltage Protection with Delay

in series with the drain of the top FET. Current limit is

•

Thermal Shutdown

independently adjustable for each channel.

•

Self Discharge of Output Capacitors When the

The LM2642 features analog soft-start circuitry that is

Regulator is OFF

independent

of

the

output

load

and

output

capacitance. This makes the soft-start behavior more

•

TSSOP package

predictable and controllable than traditional soft-start

circuits.

APPLICATIONS

A PGOOD1 pin is provided to monitor the dc output

•

Embedded Computer Systems

of channel 1. Over-voltage protection is available for

•

High End Gaming Systems

both outputs. A UV-Delay pin is also available to

•

Set-top Boxes

allow delayed shut off time for the IC during an output

under-voltage event.

•

WebPAD

BLOCK DIAGRAM

1

Please be aware that an important notice concerning availability, standard warranty, and use in critical applications of

Texas Instruments semiconductor products and disclaimers thereto appears at the end of this data sheet.

2

All trademarks are the property of their respective owners.

PRODUCTION DATA information is current as of publication date.

Copyright © 2002–2013, Texas Instruments Incorporated

Products conform to specifications per the terms of the Texas

Instruments standard warranty. Production processing does not

necessarily include testing of all parameters.