LM2653

1.5A High Efficiency Synchronous Switching Regulator

General Description

The LM2653 switching regulator provides high efficient

power conversion over a 100:1 load range (1.5A to 15 mA).

This

feature

makes

the

LM2653

an

ideal

fit

in

battery-powered applications.

Synchronous rectification is used to achieve up to 97%

efficiency. At light loads, the LM2653 enters a low power

hysteretic or “sleep” mode to keep the efficiency high. In

many applications, the efficiency still exceeds 80% at 15 mA

load. A shutdown pin is available to disable the LM2653 and

reduce the supply current to 7µA.

All the power, control, and drive functions are integrated

within the ICs. The ICs contain patented current sensing

circuity for current mode control. This feature eliminates the

external

current

sensing

resistor

required

by

other

current-mode DC-DC converters.

The ICs have a 300 kHz fixed frequency internal oscillator.

The high oscillator frequency allows the use of extremely

small, low profile components.

Protection features include thermal shutdown, input under-

voltage lockout, adjustable soft-start, cycle by cycle current

limit, output overvoltage and undervoltage protections.

Features

n

Efficiency up to 97%

n

4V to 14V input voltage range

n

1.5V to 5.0V adjustable output voltage

n

0.1

Ω Switch On Resistance

n

300 kHz fixed frequency internal oscillator

n

7 µA shutdown current

n

Patented current sensing for current mode control

n

Input undervoltage lockout

n

Output overvoltage shutdown protection

n

Output undervoltage shutdown protection

n

Adjustable soft-start

n

Adjustable PGOOD delay

n

Current limit and thermal shutdown

Applications

n

Webpad

n

Personal digital assistants (PDAs)

n

Computer peripherals

n

Battery-powered devices

n

Notebook computer video supply

n

Handheld scanners

n

GXM I/O and core voltage

n

High efficiency 5V conversion

Typical Application

Efficiency vs Load Current

(V

10104902

10104930

March 2001

© 2001 National Semiconductor Corporation

DS101049

www.national.com