FB

LM1770

HG

LG

GND

LM1770

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SNVS403C – SEPTEMBER 2005 – REVISED APRIL 2013

LM1770 Low-Voltage SOT-23 Synchronous Buck Controller With No External

Compensation

Check for Samples: LM1770

1

FEATURES

DESCRIPTION

The

LM1770

is

an

efficient

synchronous

buck

2

•

Input Voltage Range of 2.8V to 5.5V

switching controller in a tiny SOT-23 package. The

•

0.8V Reference Voltage

constant on-time control scheme provides a simple

•

No Compensation Required

design free of compensation components, allowing

minimal component count and board space. It also

•

Constant Frequency Across Input Range

incorporates a unique input feed-forward to maintain

•

Low Quiescent Current of 400µA

a constant frequency independent of the input

•

Internal Soft-start

voltage. The LM1770 is optimized for a low voltage

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

•

Short Circuit Protection

adjustable output as low as 0.8V. Driving an external

•

5-Pin SOT-23 Package

high side PFET and low side NFET it can provide

efficiencies as high as 95%.

APPLICATIONS

Three

versions

of

the

LM1770

are

available

•

Simple To Design, High Efficiency Step Down

depending on the switching frequency desired for the

Switching Regulators

application. Nominal switching frequencies are in the

•

Set-Top Boxes

range of 100kHz to 1000kHz.

•

Cable Modems

•

Printers

•

Digital Video Recorders

•

Servers

Typical Application Circuit

1

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Texas Instruments semiconductor products and disclaimers thereto appears at the end of this data sheet.

2

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PRODUCTION DATA information is current as of publication date.

Copyright © 2005–2013, Texas Instruments Incorporated

Products conform to specifications per the terms of the Texas

Instruments standard warranty. Production processing does not

necessarily include testing of all parameters.