1

LT1111

33 F

SUMIDA

CD54-220M

22

µH

LT1111 • TA01

µ

MBRS120T3

5V

100mA

GND

SW2

SW1

LIM

I

IN

V

LT1111CS8-5

SENSE

3V INPUT

10 F*

µ

+

*OPTIONAL

+

Micropower

DC/DC Converter

Adjustable and Fixed 5V, 12V

All Surface Mount 3V to 5V Step-Up Converter

DESCRIPTIO

S

FEATURE

S

APPLICATI

Typical Load Regulation

0

LOAD CURRENT (mA)

0

1

2

3

4

5

6

50

100

150

200

LT1111 • TA02

25

75

125

175

2.6

2.8

3V

s

Operates at Supply Voltages from 2V to 30V

s

72kHz Oscillator

s

Works with Surface Mount Inductors

s

Only Three External Components Required

s

Step-Up or Step-Down Mode

s

Low-Battery Detector Comparator On-Chip

s

User Adjustable Current Limit

s

Internal 1A Power Switch

s

Fixed or Adjustable Output Voltage Versions

s

Space Saving 8-Pin MiniDIP or SO-8 Package

s

3V to 5V, 5V to 12V Converters

s

9V to 5V, 12V to 5V Converters

s

Remote Controls

s

Peripherals and Add-On Cards

s

Battery Backup Supplies

s

Uninterruptible Supplies

s

Laptop and Palmtop Computers

s

Cellular Telephones

s

Portable Instruments

s

Flash Memory VPP Generators

APPLICATI

TYPICAL

The LT1111 is a versatile micropower DC/DC converter.

The device requires only three external components to

deliver a fixed output of 5V or 12V. Supply voltage ranges

from 2V to 12V in step-up mode and to 30V in step-down

mode. The LT1111 functions equally well in step-up, step-

down, or inverting applications.

The LT1111 oscillator is set at 72kHz, optimizing the

device to work with off-the-shelf surface mount inductors.

The device can deliver 5V at 100mA from a 3V input in

step-up mode or 5V at 200mA from a 12V input in step-

down mode.

Switch current limit can be programmed with a single

resistor. An auxiliary open-collector gain block can be

configured as a low-battery detector, linear post regulator,

undervoltage lock-out circuit, or error amplifier.

For input sources of less than 2V use the LT1110.