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LM1771

SNVS446D – JUNE 2006 – REVISED JANUARY 2016

LM1771 Low-Voltage Synchronous Buck Controller With Precision Enable and No

External Compensation

1 Features

3 Description

The LM1771 device is an efficient synchronous buck

1

•

Input Voltage Range of 2.8 V to 5.5 V

switching controller with a precision enable requiring

•

0.8-V Reference Voltage

no external compensation. The constant ON-time

•

Precision Enable

control scheme provides a simple design free of

compensation

components,

allowing

minimal

•

No Compensation Required

component count and board space. The precision

•

Constant Frequency Across Input Range

enable pin allows flexibility in sequencing multiple

•

Low Quiescent Current of 400 µA

rails

and

setting

UVLO.

The

LM1771

also

incorporates a unique input feedforward to maintain a

•

Internal Soft-Start

constant frequency independent of the input voltage.

•

Short Circuit Protection

The LM1771 is optimized for a low-voltage input

•

6-Pin WSON Package and 8-Pin VSSOP Package

range of 2.8 V to 5.5 V and can provide an adjustable

output as low as 0.8 V. Driving an external high-side

2 Applications

PFET and low-side NFET, it can provide efficiencies

as high as 95%.

•

Simple-to-Design, High-Efficiency, Step-Down

Switching Regulators

Three

versions

of

the

LM1771

are

available

depending on the switching frequency desired for the

•

FPGAs, DSPs, and ASIC Power Supplies

application. Nominal switching frequencies are in the

•

Set-Top Boxes

range of 100 kHz to 1000 kHz.

•

Cable Modems

•

Printers

Device Information(1)

PART NUMBER

PACKAGE

BODY SIZE (NOM)

•

Digital Video Recorders

WSON (6)

3.00 mm × 3.00 mm

•

Servers

LM1771

VSSOP (8)

3.00 mm × 3.00 mm

•

Graphic Cards

(1) For all available packages, see the orderable addendum at

the end of the data sheet.

Typical Application Circuit

1

An IMPORTANT NOTICE at the end of this data sheet addresses availability, warranty, changes, use in safety-critical applications,

intellectual property matters and other important disclaimers. PRODUCTION DATA.