MP28255 Datasheet, PDF (1/14 Pages) Monolithic Power Systems – 21V, 4A, 500kHz Synchronous Step-down Converter

The Future of Analog IC Technology
MP28255
21V, 4A, 500kHz
Synchronous Step-down Converter
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
• Low R_DS(ON) Internal Power MOSFETs
• 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
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“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
4.5V-21V
VIN
PG
ON/OFF
1
IN
6
BST
C1
22uF
9 _PG
R3
100K
11 _VCC
C3
0.1uF
MP28255
7
EN/SYNC
C4
0.1uF
L1
2uH
2,3,4,5
SW
8
FB
10
SS
Rt
24K
C5
47nF
GND AGND
12,13 ¹⁴
R1
4.99K
R2
10K
C2
47uF
1.2V/4A
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.