LT3681

1

3681f

36V, 2A, 2.8MHz Step-Down

Switching Regulator with

Integrated Power Schottky Diode

monolithic buck switching regulator that accepts input

voltages up to 34V (36V maximum). A high efficiency

0.18

Ω switch is included on the die along with a boost

Schottky diode and the necessary oscillator, control, and

logic circuitry. An undedicated power Schottky diode is

integrated into the LT3681 to minimize the solution size.

Current mode topology is used for fast transient response

and good loop stability. Low ripple Burst Mode operation

maintains high efficiency at low output currents while

keeping output ripple below 15mV in a typical application.

In addition, the LT3681 can further enhance low output

current efficiency by drawing bias current from the output

current to less than 1µA while a resistor and capacitor on

the RUN/SS pin provide a controlled output voltage ramp

90% of the programmed output voltage. The LT3681

is available in 14-Pin 4mm x 3mm DFN package with

exposed pads for low thermal resistance.

36V Maximum

Ω On-Resistance

(4mm x 3mm) DFN Package

5V Step-Down Converter

APPLICATIO S

FEATURES

DESCRIPTIO

TYPICAL APPLICATIO

SW

DC

DA

BIAS

FB

PG

RT

BD

6.3V TO

34V

5V

2A

4.7

mF

0.47

mF

330pF

22

mF

200k

20k

60.4k

L

6.8

mH

590k

GND

OFF ON

LT3681

3681 TA01

RUN/SS

BOOST

L: NEC PLC-0745-6R8

Efficiency

0.0001

10

20

0

0.001

0.01

0.1

1

10

3681 TA01b

40

30

100

90

80

60

70

50

0.0001

0.0100

0.0010

10.0000

1.0000

0.1000

L = 4.7

mH

F = 800 kHz

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

Burst Mode is a registered trademark of Linear Technology Corporation. All other

trademarks are the property of their respective owners.