MP28255

21V, 4A, 500kHz

Synchronous Step-down Converter

MP28255 Rev. 1.01

www.MonolithicPower.com

1

3/11/2011

MPS Proprietary Information. Patent Protected. Unauthorized Photocopy and Duplication Prohibited.

© 2011 MPS. All Rights Reserved.

The Future of Analog IC Technology

DESCRIPTION

The MP28255 is a high frequency synchronous

rectified step-down switch mode converter with

built in internal power MOSFETs. It offers a

very compact solution to achieve 4A continuous

output current over a wide input supply range

with excellent load and line regulation. The

MP28255 operates at high efficiency over a

wide output current load range.

Current mode operation provides fast transient

response and eases loop stabilization.

Full protection features include OCP and thermal

shut down.

The MP28255 requires a minimum number of

readily available standard external components

and is available in a space saving 3mm x 4mm

14-pin QFN package.

FEATURES

• Wide 4.5V to 21V Operating Input Range

• 4A Output Current

• Proprietary

Switching

Loss

Reduction

Technique

• Fixed 500kHz Switching Frequency

• External Soft-Start

• Sync from 300kHz to 2MHz External Clock

• Internal Compensation

• Integrated Bootstrap Diode

• Over-Current Protection and Hiccup

• Thermal Shutdown

• Output Adjustable from 0.8V

• Available in 14-pin QFN3x4 Package

APPLICATIONS

•

Networking Systems

•

Digital Set Top Boxes

•

Personal Video Recorders

•

Flat Panel Television and Monitors

•

Distributed Power Systems

For MPS green status, please visit MPS website under Quality Assurance.

“MPS” and “The Future of Analog IC Technology” are Registered Trademarks of

Monolithic Power Systems, Inc.

The information in this datasheet about the product and its associated

technologies are proprietary and intellectual property of Monolithic Power

Systems and are protected by copyright and pending patent applications

TYPICAL APPLICATION

C1

22uF

MP28255

SW

SS

GND

AGND

FB

EN/SYNC

IN

BST

VCC

PG

PG

C4

0.1uF

C5

47nF

R2

10K

Rt

24K

1.2V/4A

R1

4.99K

R3

100K

L1

2uH

C2

47uF

C3

0.1uF

VIN

ON/OFF

8

10

6

2,3,4,5

1

11

9

7

12,13

4.5V-21V

14