Date: /5/06

SP7650 Wide Input Voltage Range 3A, 300kHz, Buck Regulator

© Copyright 2006 Sipex Corporation

1

Date: 2/16/06

SP7650 Wide Input Voltage Range 3A, 300kHz, Buck Regulator

© Copyright 2006 Sipex Corporation

FEATURES

■

2.5V to 28V Step Down Achieved Using Dual Input

■

Output Voltage down to 0.8V

■

3A Output Capability

■

■

Highly Integrated Design, Minimal Components

■

300 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

95% Possible

■

Asynchronous Start-Up into a Pre-Charged Output

■

Small 7mm x 4mm DFN Package

■

U.S. Patent #6,922,041

The SP7650 is a synchronous step-down switching regulator optimized for high efficiency. The part is designed to be

especially attractive for dual supply, 12V or 24V distributed power systems stepped down with 5V used to power the

SP7650 is designed to provide a fully integrated buck regulator solution using a fixed 300kHz frequency, PWM voltage

mode architecture. Protection features include UVLO, thermal shutdown and output short circuit protection. The

SP7650 is available in the space saving DFN package

.

TYPICAL APPLICATION CIRCUIT

Now Available in Lead Free Packaging

DESCRIPTION

1

2

3

4

5

6

7

8

9

10

11

12

13

14

15

16

17

18

19

20

21

22

23

24

25

26

BOTTOM VIEW

Heatsink Pad 1

Connect to Lx

Heatsink pad 2

Connect to GND

Heatsink pad 3

Connect to VIN

GND

COMP

UVIN

GND

SS

LX

LX

LX

LX

GND

GND

GND

BST

NC

LX

LX

LX

DFN PACKAGE

7mm x 4mm

SP7650

CBST

6800pF

L1

2.2uH, Irate=4.78A

C1

22uF

CVCC

2.2uF

U1

SP7650

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

47nF

CP1

22pF

3.3V

0-3A

RSET

21.5k ,1%

GND

C3

47uF

Notes:

12V

VIN

1. U1 Bottom-Side Layout should

have 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=300Khz

+5V VCC

ENABLE

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

(KOhm)

16V

6.3V

(note 2)

SP7650

Wide Input Voltage Range 3A,

1

2

3

4

5

6

7

8

9

10

11

12

13

14

15

16

17

18

19

20

21

22

23

24

25

26

BOTTOM VIEW

Heatsink Pad 1

Connect to Lx

Heatsink Pad 2

Connect to GND

Heatsink Pad 3

GND

COMP

NC

LX

LX

LX

LX

BST

LX

LX

LX

DFN PACKAGE

7mm x 4mm

SP7650

SS

GND

GND

GND

Pin 27

Pin 28

Pin 29

GND