LT3740

1

3740fc

TYPICAL APPLICATION

FEATURES

APPLICATIONS

DESCRIPTION

Wide Operating Range,

Synchronous Step-Down Controller

regulator controller that drives N-channel power MOSFET

stages. The controller uses valley current mode architecture

to achieve very low duty cycles with excellent transient

response without requiring a sense resistor.

The LT3740 includes an internal step-up converter to

provide a bias 7.8V higher than the input voltage for the

drive. This enables the part to work from an input voltage

as low as 2.2V.

The XREF pin is an external reference input that allows the

user to override the internal 0.8V feedback reference with

any lower value, allowing full control of the output voltage

during operation, output voltage tracking or soft-start.

The LT3740 has three current limit levels that can be

chosen by connecting the RANGE pin to ground, open,

and input respectively.

High Efficiency Step-Down Converter

× 3mm DFN

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

property of their respective owners.

Efficiency vs Load Current

SWB

SHDN

XREF

RANGE

BGDP

BIAS

TGATE

SW

SN

+

BGATE

GND

LT3740

SN

–

PGND

FB

3740 TA01a

0.9μH

1μF

0.22μF

1.8V

10A

3V to 12V

M1

HAT2168H

M2

HAT2165H

100μF

3

10μF

39pF

22μH

20k

15k

1nF

22pF

80.6k

105k

15k

1Ω

1Ω

D1

B320A

1Ω

LOAD CURRENT (A)

0

86

92

88

90

94

3740 TA01b

84

82

80

46

2

8

10