NB679

28V, Low Iq, High Current, Fixed 5V-8A

Synchronous Buck Converter

with 100 mA LDO

NB679 Rev. 1.03

www.MonolithicPower.com

1

7/27/2017

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

© 2017 MPS. All Rights Reserved.

DESCRIPTION

The NB679 is a fully integrated, high-frequency,

synchronous, rectified, step-down switch-mode

converter with a fixed 5 V output. It offers a very

compact solution to achieve 8 A continuous

output current and 10 A peak output current

over a wide input supply range with excellent

load and line regulation.

The NB679 operates at high efficiency over a

wide output current load range based on MPS

proprietary switching loss reduction technology

and internal low Ron power MOSFETs.

Adaptive constant-on-time (COT) control mode

provides fast transient response and eases loop

stabilization. The DC auto-tune loop provides

good load and line regulation.

NB679 provides a fixed 5 V LDO, which can be

used to power the external peripheries.

Full protection features include OC limit, OVP,

UVP, and thermal shutdown.

The converter requires a minimum number of

external components and is available in QFN

2mm x 3mm package.

FEATURES

 Wide 5.5 V to 28 V Operating Input Range

 Fixed 5 V Vout

 Supports 5.5 V-5 V

 Ultrasonic Mode with Fs over 25 kHz

 100 μA Low Quiescent Current

 8 A Continous Output Current

 10 A Peak Output Current

 Adaptive COT for Fast Transient

 DC Auto-Tune Loop for Load Regulation

 Stable with POSCAP and Ceramic Output

Capacitors

 Built-In 5 V, 100 mA LDO with Switch Over

 1% Reference Voltage

 Internal Soft Start

 Output Discharge

 700 kHZ Switching Frequency

 OCP, OVP, UVP, and Thermal Shutdown.

 Latch-Off Reset via EN or Power Cycle

 QFN-12 (2mm x 3mm) Package

APPLICATIONS



Laptop Computers



Tablet PCs



Networking Systems



Personal Video Recorders



Flat Panel Television and Monitors



Distributed Power Systems

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

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

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

Monolithic Power Systems, Inc.

TYPICAL APPLICATION

EN

VOUT

BST

LDO

VIN

PG

SW

GND

VIN

GND

ENLDO

NB679

PGND

VOUT

5 V/8 A

VCC

22 μF

220 nF

1μF

100 kΩ

1.5 μH

88 μF

4.7 μF

AGND

3.3 Ω

5.5 V-24 V

EN

5 V/ 100

mA

ENLDO