LM2731

0.6/1.6 MHz Boost Converters With 22V Internal FET

Switch in SOT-23

General Description

The LM2731 switching regulators are current-mode boost

converters operating at fixed frequencies of 1.6 MHz (“X”

option) and 600 kHz (“Y” option).

The use of SOT-23 package, made possible by the minimal

power loss of the internal 1.8A switch, and use of small

inductors and capacitors result in the industry’s highest

power density. The 22V internal switch makes these solu-

tions perfect for boosting to voltages up to 20V.

These parts have a logic-level shutdown pin that can be

used to reduce quiescent current and extend battery life.

Protection is provided through cycle-by-cycle current limiting

and thermal shutdown. Internal compensation simplifies de-

sign and reduces component count.

Switch Frequency

XY

1.6 MHz

0.6 MHz

Features

n

22V DMOS FET switch

n

1.6 MHz (“X”), 0.6 MHz (“Y”) switching frequency

n

Low R

n

Switch current up to 1.8A

n

Wide input voltage range (2.7V–14V)

n

n

5-Lead SOT-23 package

n

Uses tiny capacitors and inductors

n

Cycle-by-cycle current limiting

n

Internally compensated

Applications

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White LED Current Source

n

PDA’s and Palm-Top Computers

n

Digital Cameras

n

Portable Phones and Games

n

Local Boost Regulator

Typical Application Circuit

20059110

20059130

July 2003

© 2003 National Semiconductor Corporation

DS200591

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