7

APPLICATION CIRCUIT FOR 12V INPUT

Figure 12 shows another example of the SP7655ER configured for a common Bus

Voltage conversion from +12V input to 3.3V output at 8A.

Figure 12. SP7655ER configured for Vin = 12V, Vout = 3.3V at 0-8A Output Load

Current

Figure 13. Efficiency vs Load

Figure 14. Load Regulation

Figure 15. Load Step Response: 5-8A

Figure 16. Load Step Response: 0-6A

All resistor & capacitor size

0603 unless other wise specify

CBST

1uF

R3

200k,1%

L1 IHLP-2525CZ-01-2R2MTR

2.2uH, Irate=8A

U2

SPX5205

VIN

1

GND

2

EN

3

BYP

4

VOUT

5

C1

3.3uF

CVCC

2.2uF

U1

SP7655

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

15pF

3.30V

0-8A

50V

R2

21.5k,1%

GND

C3

47uF

C3

CERAMIC

1210

X5R

C4

3.3uF

6.3V

Notes:

12V

DCR=10.4mOhm

VIN

SD101AWS

U1 Bottom-Side Layout should has

three Contacts which are

isolated from one of another, QT

& QB Drain Contact and

Controller GND Contact

VOUT

RZ3

8.66k,1%

GND2

R4

100k,1%

C2

0.1uF

C1,C4

CERAMIC

1210

Y5V

50V

CZ3

120pF

CZ2

2,200pF

R1

68.1k,1%

RZ2

7.68k,1%

CF1

100pF

fs=300Khz

Efficiency vs Load (12V to 3.3V)

60

70

80

90

100

01

2345

678

Load Current (A)

Iout (2A/div)

Iout (2A/div)

Vout

Vout

Load Regulation (12V to 3.3V)

3.300

3.305

3.310

3.315

3.320

3.325

3.330

3.335

3.340

0.5

123

4

567

8

Output Current (A)