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Date: 08/25/04

SP7651 Wide Input Voltage Range 3A, 900kHz, Buck Regulator

© Copyright 2004 Sipex Corporation

SP7651

FEATURES

■ 2.5V to 20V Step Down Achieved Using Dual Input

■ Output Voltage down to 0.8V

■ 3A Output Capability (Up to 5A with Air Flow)

■ Highly Integrated Design, Minimal Components

■ 900 kHz Fixed Frequency Operation

■ Over Temperature Protection

■ Short Circuit Protection with Auto-Restart

■ Wide BW Amp Allows Type II or III Compensation

■ Programmable Soft Start

■ Fast Transient Response

■ High Efficiency: Greater than 92% Possible

■ Asynchronous Start-Up into a Pre-Charged Output

■ Small 7mm x 4mm DFN Package

Wide Input Voltage Range 3A, 900kHz, Buck Regulator

The SP7651 is a high voltage synchronous step-down switching regulator optimized for high efficiency. The part is

voltage minimizes power dissipation in the part. The SP7651 is designed to provide a fully integrated buck regulator

solution using a fixed 900kHz frequency, PWM voltage mode architecture. Protection features include UVLO, thermal

shutdown and output short circuit protection. The SP7651 is available in the space saving 7mm X 4mm DFN package

.

®

Advanced

TYPICAL APPLICATION CIRCUIT

Now Available in Lead Free Packaging

DESCRIPTION

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26

TOP VIEW

Heatsink Pad 1

Connect to Lx

Heatsink pad 2

Connect to GND

Heatsink pad 3

Connect to V

IN

GND

COMP

UVIN

GND

SS

LX

LX

LX

LX

GND

GND

GND

BST

NC

LX

LX

LX

DFN PACKAGE

7mm x 4mm

SP7651

CBST

6800pF

L1

4.7uH, Irate=3.87A

C1

22uF

CVCC

2.2uF

U1

SP7651

PGND

1

PGND

2

PGND

3

GND

4

VFB

5

COMP

6

UVIN

7

GND

8

SS

9

VIN

10

VIN

11

VIN

12

VIN

13

LX

14

LX

15

LX

16

NC

17

BST

18

GND

19

GND

20

GND

21

VCC

22

LX

23

LX

24

LX

25

LX

26

DBST

CSS

15nF

CP1

22pF

3.3V

0-3A

RSET

21.5k,1%

GND

C3

22uF

Notes:

12V

VIN

1. U1 Bottom-Side Layout should

has three contacts isolated from

one another Vin SWNODE and GND

SD101AWS

VOUT

RZ3

7.15k,1%

CZ3

150pF

CZ2

1,000pF

R1

68.1k,1%

RZ2

15k,1%

CF1

100pF

fs=900Khz

+5V VCC

ENABLE

2. RSET=54.48/(Vout-0.8V)

(KOhm)

6.3V

(note 2)

16V