LT3686



3686fa

ApplicAtions

37V/1.2A Step-Down

Regulator in 3mm

× 3mm DFN

converter with an internal 1.2A power switch, packaged in

10-lead 3mm

× 3mm DFN. The wide input range of 3.6V to

37V makes the LT3686 suitable for regulating power from

awidevarietyofsources,including24Vindustrialsupplies

and automotive batteries. Its high maximum frequency al-

lows the use of tiny inductors and capacitors, resulting in

a very small solution. Operating frequency above the AM

band avoids interfering with radio reception, making the

LT3686 particularly suitable for automotive applications.

Cycle-by-cycle current limit and DA current sense provide

protectionagainstfaultconditions.Soft-startandfrequency

foldback eliminate input current surge during start-up. An

optional internal regulated active load at the output via the

BDpinkeepstheLT3686atfullswitchingfrequencyatlight

loads, resulting in low, predictable output ripple above the

audioandAMbands.Internalcompensationandaninternal

boost diode reduce external component count.

L

, LT, LTC, LTM, Linear Technology and the Linear logo are registered trademarks of Linear

Technology Corporation. All other trademarks are the property of their respective owners.

3.3V Step-Down Converter

SW

DA

FB

MODE

SS

RT

6V TO 37V

BD

3.3V

1.2A

0.22µF

MBRM140

2.2µF

10nF

15.4k

22µF

10k

6.8µH

31.6k

GND

LT3686

3686 TA01a

EN/UVLO

BOOST

FeAtures

Description

n

Automotive Systems

n

Battery-Powered Equipment

n

Wall Transformer Regulation

n

Distributed Supply Regulation

n

Wide Input Range:

Operation from 3.6V to 37V

Overvoltage Lockout Protects Circuit Through

55V Transients

n

Low Minimum On-Time:

n

1.2A Output Current

n

Adjustable Frequency: 300kHz to 2.5MHz

n

Constant Switching Frequency at Light Loads

n

Tracking and Soft-Start

n

Precision UVLO

n

Short-Circuit Robust

n

n

Internally Compensated

n

10-Lead 3mm

× 3mm DFN Package

typicAl ApplicAtion

LOAD CURRENT (mA)

0

0

10

30

40

50

70

400

800

1000

3686 TA01b

20

80

90

60

200

600

1200