NB621

8A, 25V, 600kHz Synchronous Step-Down

Converter with Integrated LDO

NB621 Rev. 0.9

www.MonolithicPower.com

1

12/10/2013

MPS Proprietary Information. Unauthorized Photocopy and Duplication Prohibited.

© 2013 MPS. All Rights Reserved.

The Future of Analog IC Technology

DESCRIPTION

The NB621 is a high frequency synchronous

rectified step-down switch mode converter with

a built in internal high side power MOSFET and

integrated LDO. It offers a very compact

solution to achieve 8A continuous output

current over a wide input, load and line range.

Current mode operation provides fast transient

response and eases loop stabilization.

Full protection features include OCP and thermal

shut down.

The NB621 requires a minimum number of

readily available standard external components

and is available in a space saving 4mm x 5mm

28-pin QFN package.

FEATURES

• Wide 5.5V to 25V Operating Input Range

• 8A Output Current

• Fixed 600kHz switching frequency

• Sync from 300kHz to 2MHz External Clock

• Integrated 100mA LDO

• Internal Compensation

• Power Good Output

• Integrated Bootstrap Diode

• OCP Protection and Thermal Shutdown

• Output Adjustable from 0.8V to 15V

• Available in 4mm x 5mm 28-pin QFN package.

APPLICATIONS

•

Notebook Systems and I/O Power

•

Networking Systems

•

Digital Set Top Boxes

•

Personal Video Recorders

•

Flat Panel Television and Monitors

•

Distributed Power Systems

“MPS” and “The Future of Analog IC Technology” are Registered Trademarks of

Monolithic Power Systems, Inc.

TYPICAL APPLICATION (FOR NOTEBOOK)

VCC

VIN

VCC

GND

VCC

U1

IN

VCC

AAM

PGOOD

EN/SYNC

ENLDO

SS GND SELH

NC

LDO

REGO

SDRV

FB

SW

BST

NB621EV

AAM

R3

100k

R4

60.4k

R5

20k

R2

100k

R1

100k

R11

61.9k

R12

20.0k

R13

1k

3.3V

R8

100k

R14

10k

R9

22k

PGOOD

EN

ENLDO

GND

VOUT

VIN

17,18,19,20,21

11

12

15

16

23

6,9,24,27,28

25

26

8

14

2,3,4,5

1

Q1

FDS6670AS