1

LT1371

500kHz High Efficiency

3A Switching Regulator

The LT

switching regulator. It can be operated in all standard

switching configurations including boost, buck, flyback,

forward, inverting and “Cuk.” A 3A high efficiency switch

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

protection circuitry.

The LT1371 typically consumes only 4mA quiescent

current and has higher efficiency than previous parts.

High frequency switching allows for very small inductors

to be used.

New design techniques increase flexibility and maintain

ease of use. Switching is easily synchronized to an exter-

nal logic level source. A logic low on the Shutdown pin

reduces supply current to 12

µA. Unique error amplifier

circuitry can regulate positive or negative output voltage

while maintaining simple frequency compensation tech-

niques. Nonlinear error amplifier transconductance re-

duces output overshoot on start-up or overload recovery.

Oscillator frequency shifting protects external compo-

nents during overload conditions.

s

Faster Switching with Increased Efficiency

s

Uses Small Inductors: 4.7

µH

s

All Surface Mount Components

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Low Minimum Supply Voltage: 2.7V

s

Quiescent Current: 4mA Typ

s

Current Limited Power Switch: 3A

s

Regulates Positive or Negative Outputs

s

Shutdown Supply Current: 12

µA Typ

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Easy External Synchronization

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Boost Regulators

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Laptop Computer Supplies

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Multiple Output Flyback Supplies

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Inverting Supplies

5V to 12V Boost Converter

OUTPUT CURRENT (A)

0.01

50

60

70

80

90

0.1

1

LT1371 • TA02

100

12V Output Efficiency

LT1371

5V

GND

FB

LT1371 • TA01

S/S

L1*

4.7

µH

C1**

22

µF

25V

C4**

22

µF

25V

× 2

C2

0.047

µF

C3

0.0047

µF

R3

2k

R2

6.19k

1%

R1

53.6k

1%

†

12V

D1

MBRS330T3

ON

OFF

*

**

COILCRAFT DO3316P-472 (4.7

µH),

DO3316P-103 (10

µH) OR

SUMIDA CD104-100MC (10

µH)

AVX TPSD226M025R0200

+

+

L1

4.7

µH

10

µH

0.7A

0.8A

OUT

FEATURES

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