MPQ28261

21V, 3A, 500kHz Synchronous

Step-Down Coverter

MPQ28261 Rev. 1.12

www.MonolithicPower.com

1

10/10/2013

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

© 2013 MPS. All Rights Reserved.

The Future of Analog IC Technology

DESCRIPTION

The MPQ28261 is a synchronous, rectified,

step-down, switch-mode converter with built-in

120mΩ high-side MOSFET and 20mΩ low-side

MOSFET. It offers a very compact solution to

achieve a continuous 3A output current over a

wide input supply range, with excellent load and

line regulation. Its synchronous mode operation

increases its efficiency over its output current

load range, and uses a fixed 500kHz switching

frequency.

Current mode operation provides a fast

transient

response

and

improves

loop

stabilization. Full protection features include

over-current protection and thermal shut down.

The MPQ28261 has an external SS pin to

program the soft-start time and power-good

signal output.

The MPQ28261 requires a minimal number of

readily-available standard external components

and is available in a space saving 3mmx4mm

14-pin QFN package.

FEATURES

• Wide 4.5V-to-21V Operating Input Range

• 3A Maximum Continuous Output Current

• Integrated 120mΩ High-Side and 20mΩ

Low-Side Power MOSFETs

• 1% Reference Voltage Accuracy

• Up to 85% Efficiency (for Drops of 12V to

1.2V)

• Fixed 500kHz Switching Frequency

• External Soft-Start

• PG Output

• OCP and Thermal Shutdown

• Output Adjustable from 0.603V to 18V

• Available in a 3mm x 4mm 14-pin QFN

Package.

APPLICATIONS

• DSL Modems

• Cable Modems

• Set-Top Boxes

• Telecom

All MPS parts are lead-free and adhere to the RoHS directive. For MPS green

status, please visit MPS website under Products, Quality Assurance page.

“MPS” and “The Future of Analog IC Technology” are registered trademarks of

Monolithic Power Systems, Inc.

TYPICAL APPLICATION

L1

2.8uH

C3

0.1uF

C1

22uF

C2

47uF

AGND

FB

SW

BST

IN

PG

EN

4.5V-21V

MPQ28261

VOUT

1.2V/3A

R10

100K

VCC

C4

0.1uF

R1

10K

R2

10K

ON/OFF

1

9

11

7

14

6

2,3,4,5

8

Rt

24K

VIN

VCC

SS

C7

47nF

GND

12,13

10

Efficiency vs. Load Current

LOAD CURRENT (A)

0

10

20

30

40

50

60

70

80

90

100

00.5

11.5

22.5

33.5

V

V

V