Electrical Specifications Subject to Change

LT8611

1

8611p

TYPICAL APPLICATION

FEATURES

DESCRIPTION

42V, 2.5A Synchronous

Step-Down Regulator with

Current Sense and 2.5µA

Quiescent Current

synchronous monolithic step-down switching regulator

that consumes only 2.5μA of quiescent current. Top and

bottom power switches are included with all necessary

circuitry to minimize the need for external components.

The built-in current sense amplifier with monitor and

control pins allows accurate input or output current

regulation and limiting. Low ripple Burst Mode operation

enables high efficiency down to very low output currents

pin allows synchronization to an external clock. Internal

compensation with peak current mode topology allows

the use of small inductors and results in fast transient

response and good loop stability. The EN/UV pin has an

undervoltage lockout or to shut down the LT8611 reduc-

ing the input supply current to 1μA. A capacitor on the

TR/SS pin programs the output voltage ramp rate during

the programmed output voltage as well as fault conditions.

The LT8611 is available in a small 24-lead 3mm

× 5mm

QFN package with exposed pad for low thermal resistance.

5V Step-Down Converter with 2.5A Output Current Limit

APPLICATIONS

n

Rail-to-Rail Current Sense Amplifier with Monitor

n

Wide Input Voltage Range: 3.4V to 42V

n

n

High Efficiency Synchronous Operation:

n

Fast Minimum Switch-On Time: 50ns

n

Low Dropout Under All Conditions: 200mV at 1A

n

Allows Use Of Small Inductors

n

Low EMI

n

Adjustable and Synchronizable: 200kHz to 2.2MHz

n

Current Mode Operation

n

Accurate 1V Enable Pin Threshold

n

Internal Compensation

n

Output Soft-Start and Tracking

n

Small Thermally Enhanced 3mm

× 5mm 24-Lead

QFN Package

n

Automotive and Industrial Supplies

n

General Purpose Step-Down

n

CCCV Power Supplies

L, LT, LTC, LTM, Burst Mode, Linear Technology and the Linear logo are registered trademarks

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

owners.

LOAD CURRENT (A)

0

80

90

100

2

8611 TA01b

70

60

75

85

95

65

55

50

0.5

1

1.5

2.5

BST

EN/UV

ON OFF

SYNC

IMON

ICTRL

TR/SS

RT

SW

LT8611

GND

PGND

ISP

BIAS

ISN

PG

8611 TA01a

FB

0.1μF

5V

2.5A

1μF

47μF

4.7μF

5.5V TO 42V

0.1μF

1μF

10pF

4.7μH

0.02Ω

1M

243k

52.3k