NB679A

28V, Low IQ, Fixed 5.1V, 8A,

Synchronous Buck Converter

with 100mA LDO and LP# VOUT Scaling

NB679A 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

NB679A

is

a

fully

integrated,

high-

frequency, synchronous, rectified, step-down,

switch-mode converter with a fixed 5.1V output

and low-power mode voltage scaling. It offers a

very compact

solution to

achieve an 8A

continuous output current and a 10A peak

output current over a wide input supply range

with excellent load and line regulation.

The NB679A 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.

The NB679A provides a fixed 5V 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 a

QFN-12 2mm x 3mm package.

FEATURES

 Wide 5.5V to 28V Operating Input Range

 Fixed 5.1V Vout (+2% of 5V Vout)

 LP# Output Voltage Scaling (-3% of 5V Vout)

 Supports Large Duty Operation

 Ultrasonic Mode

 100μA Low Quiescent Current

 8A Continuous Output Current and 10A

Peak Output Current

 Adaptive COT for Fast Transient

 DC Auto-Tune Loop

 Stable with POSCAP and Ceramic Output

Capacitors

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

 1% Reference Voltage

 Internal Soft Start

 Output Discharge

 700kHZ 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



Flat Panel Televisions 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

LP#

NB679A

PGND

VOUT

5.1V/8A

VCC

22μF

220nF

1μF

100kΩ

1.5μH

88μF

4.7μF

AGND

3.3Ω

5.5V-24V

EN

5V/ 100mA

LP#