1 Features

1• 22-V DMOS FET Switch

• 1.6-MHz (X Option), 0.6-MHz (Y Option) Switching

Frequency

• Low R DS(ON) DMOS FET

• Switch Current Up to 1.8 A

• Wide Input Voltage Range (2.7 V to 14 V)

• Low Shutdown Current (<1 μA)

• 5-Lead SOT-23 Package

• Uses Tiny Capacitors and Inductors

• Cycle-by-Cycle Current Limiting

• Internally Compensated

2 Applications

• White LED Current Sources

• PDAs and Palm-Top Computers

• Digital Cameras

• Portable Phones and Games

• Local Boost Regulators

3 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 1.8-A switch, and

use of small inductors and capacitors result in the

highest power density of the industry. The 22-V

internal switch makes these solutions perfect for

boosting to voltages up to 20 V.

These parts have a logic-level shutdown pin that can

reduce quiescent current and extend battery life.

Protection is provided through cycle-by-cycle current

limiting and thermal shutdown. Internal compensation

simplifies design and reduces component count.