The Future of Analog IC Technology
High Efficiency, Fast Transient, 8A, 28V
Synchronous Step-down Converter
In a Tiny QFN20 (3x4mm) Package
FEATURES
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Wide 4.5V to 28V Operating Input Range
8A Output Current
Internal 30mΩ High-Side, 12mΩ Low-Side
Power MOSFETs
Proprietary Switching Loss Reduction
Technique
1% Reference Voltage
Programmable Soft Start Time
Soft Shutdown
Programmable Switching Frequency
SCP, OCP, OVP, UVP Protection and
Thermal Shutdown
Output Adjustable from 0.8V to 13V
Available in a QFN20 (3x4mm) Package
Notebook Systems and I/O Power
Networking Systems
Optical Communication Systems
Distributed Power POL Systems
NB639
DESCRIPTION
The NB639 is a fully integrated, high frequency
synchronous rectified step-down switch mode
converter. It offers a very compact solution to
achieve 8A continuous output current over a wide
input supply range with excellent load and line
regulation. The NB639 operates at high efficiency
over a wide output current load range.
To further optimize efficiency at light load, this
device’s V
CC
supply is designed to be biased
externally.
Constant-On-Time (COT) control mode provides
fast transient response and eases loop
stabilization.
Full protection features include SCP, OCP, OVP,
UVP and thermal shutdown.
The NB639 requires a minimum number of readily
available standard external components and is
available in a space-saving QFN20 (3x4mm)
package.
APPLICATIONS
All MPS parts are lead-free and adhere to the RoHS directive. 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.
TYPICAL APPLICATION
NB639 Rev.1.13
4/18/2012
www.MonolithicPower.com
MPS Proprietary Information. Patent Protected. Unauthorized Photocopy and Duplication Prohibited.
© 2012 MPS. All Rights Reserved.
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MPS [ MONOLITHIC POWER SYSTEMS ]
