20

 2006 Semtech Corp.

www.semtech.com

SC1486A

POWER MANAGEMENT

Application Information (Cont.)

Layout Guidelines (Cont.)

In Figure 8 on Page 19, all components referenced to VSSA1 and VSSA2 have been placed and have been connected

using copper pours (left) or 0.020” traces (right). Note that there are two separate copper pours or traces, one for

VSSA1 and one for VSSA2. Decoupling capacitors C2 and C22 are as close as possible to their pins, as are VDDP

decoupling capacitors C8 and C9. C8 and C9 should connect to the ground plane using two vias each.

0603

0402

R13

17k4

VCCA1

1.8V

0402

0402

1.8V, 10A

ROUTE AS DIFFERENTIAL PAIR TO OUTPUT CAPACITORS

0402

R7

0R

0402

C20

1n

+

C13

330u/25m

VSSA1

C21

1u

R10

45k3

7343

7343

C17

27p

C12

0u1

U1

SC1486A

3

1

23

6

7

5

4

22

27

24

26

25

28

17

15

9

20

21

19

18

13

12

8

10

11

14

2

16

VDDP1

PGND1

TON1

DH1

BST1

LX1

ILIM1

EN/PSV1

PGD1

VOUT1

FB1

VCCA1

VSSA1

VDDP2

PGND2

TON2

DH2

BST2

LX2

ILIM2

PGD2

FB2

REFIN

REFOUT

VCCA2

VSSA2

DL1

DL2

0402

+

C14

330u/25m

0402

U1

SC1486A

3

1

23

6

7

5

4

22

27

24

26

25

28

17

15

9

20

21

19

18

13

12

8

10

11

14

2

16

VDDP1

PGND1

TON1

DH1

BST1

LX1

ILIM1

EN/PSV1

PGD1

VOUT1

FB1

VCCA1

VSSA1

VDDP2

PGND2

TON2

DH2

BST2

LX2

ILIM2

PGD2

FB2

REFIN

REFOUT

VCCA2

VSSA2

DL1

DL2

VCCA2

0402

VSSA2

0603

R8

0R

ROUTE AS DIFFERENTIAL PAIR TO OUTPUT CAPACITORS

0.9V

+

C15

220u/25m

0.9V, 1.5A

C22

1u

7343

C16

0u1

Figure 9: Differential Routing of Feedback and Ground Reference Traces