1

LT1072

1072fc

1.25A High Efficiency

Switching Regulator

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Available in MiniDiP, TO-220, and TO-3 Packages

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Wide Input Voltage Range 3V to 60V

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Low Quiescent Current—6mA

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Internal 1.25A Switch

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Very Few External Parts Required

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Self-Protected Against Overloads

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Operates in Nearly All Switching Topologies

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Shutdown Mode Draws Only 50µA Supply Current

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Flyback-Regulated Mode has Fully Floating Outputs

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Can be Externally Synchronized

The LT

regulator. It can be operated in all standard switching

configurations including buck, boost, flyback, forward,

inverting and “Cuk”. A high current, high efficiency switch

is included on the die along with all oscillator, control, and

protection circuitry. Integration of all functions allows the

LT1072 to be built in a standard 5-pin TO-3 or TO-220

power package as well as the 8-pin miniDlP. This makes it

extremely easy to use and provides “bust proof” operation

similar to that obtained with 3-pin linear regulators.

The LT1072 operates with supply voltages from 3V to 60V,

and draws only 6mA quiescent current. It can deliver load

power up to 20 watts with no external power devices. By

utilizing current-mode switching techniques, it provides

excellent AC and DC load and line regulation.

The LT1072 has many unique features not found even on

the vastly more difficult to use low power control chips

presently available. It uses an adaptive anti-sat switch

drive to allow very wide ranging load currents with no loss

in efficiency. An externally activated shutdown mode

reduces total supply current to 50µA typical for standby

operation. Totally isolated and regulated outputs can be

generated by using the optional “flyback regulation mode”

built into the LT1072, without the need for optocouplers or

extra transformer windings.

USER NOTE:

This data sheet is only intended to provide specifications, graphs, and a general functional

description of the LT1072. Application circuits are included to show the capability of the LT1072.

A complete design manual (AN-19) should be obtained to assist in developing new designs. This

manual contains a comprehensive discussion of both the LT1070 and the external components used

with it, as well as complete formulas for calculating the values of these components. The manual

can also be used for the LT1072 by factoring in the lower switch current rating.

, LTC and LT are registered trademarks of Linear Technology Corporation.

FEATURES

DESCRIPTIO

Boost Converter (5V to 12V)

TYPICAL APPLICATIO

10.7k

1.24k

LT1072

GND

FB

1k

1µF

–

470µF

12V, 0.25A

*REQUIRED IF INPUT LEADS ≥ 2”

**PULSE ENGINEERING 52626

220µH**

5V

+

–

C3

25µF*

+

–

LT1072 • TA01

+

Maximum Output Power*

LT1072 • TA02

INPUT VOLTAGE (V)

0

MINIDIP OUTPUT POWER MAY BE LIMITED BY PACKAGE TEMPERATURE

RISE AT HIGH INPUT VOLTAGES OR HIGH DUTY CYCLES

15

20

25

10

5

0

10

20

30

40

50

BUCK-BOOST

BUCK-BOOST

FLYBACK

ISOLATED

BOOST

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Logic Supply 5V at 2.5A

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5V Logic to ±15V Op Amp Supply

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Offline Converter up to 50W

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Battery Upconverter

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Power lnverter (+ to –) or (– to +)

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Fully Floating Multiple Outputs

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Driver for High Current Supplies

APPLICATIO S