1

LT1107

Micropower

DC/DC Converter

Adjustable and Fixed 5V, 12V

APPLICATI

TYPICAL

Efficiency

DESCRIPTIO

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FEATURE

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Operates at Supply Voltages from 2V to 30V

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Consumes Only 320

µA Supply Current

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Works in Step-Up or Step-Down Mode

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Only Three External Components Required

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Low-Battery Detector Comparator On-Chip

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User Adjustable Current Limit

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Internal 1A Power Switch

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Fixed or Adjustable Output Voltage Versions

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Space Saving 8-Pin MiniDIP or SO-8 Package

The LT1107 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 LT1107 functions equally well in step-up, step-

down, or inverting applications.

The LT1107 is pin-for-pin compatible with the LT1111, but

has a duty cycle of 70%, resulting in increased output

current in many applications. The LT1107 can deliver

150mA at 5V from a 2AA cell input and 5V at 300mA from

24V in step-down mode. Quiescent current is just 320

µA,

making the LT1107 ideal for power-conscious battery-

operated systems. The 63kHz oscillator is optimized to

work with surface mount inductors and capacitors.

Switch current limit can be programmed with a single

resistor. An auxiliary gain block can be configured as a

low-battery detector, linear post regulator, undervoltage

lock-out circuit, or error amplifier.

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APPLICATI

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Palmtop Computers

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

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24V to 5V, 12V to 5V Converters

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LCD Bias Generators

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Peripherals and Add-On Cards

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Battery Backup Supplies

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Cellular Telephones

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Portable Instruments

LOAD CURRENT (mA)

1

82

80

78

76

74

72

70

68

66

64

10

100

400

1107 TA02

+

5V

150mA

+

MBRS120T3

L1*

33

µH

47

Ω

2

× AA

ALKALINE CELLS

100

µF

SUMIDA CD54-330K

COILCRAFT DT3316-473

*

SENSE

SW1

SW2

GND

47

µF

LT1107-5

1107 TA01

Palmtop Computer Logic Supply