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 2003 Semtech Corp.

www.semtech.com

SC1480A

POWER MANAGEMENT

The layout can be considered in two parts, the control section referenced to VSSA and the power section. Looking

at the control section first, locate all components referenced to VSSA on the schematic and place these components

at the chip. Connect VSSA using either a wide (>0.020”) trace or a copper pour if room allows. Very little current

flows in the chip ground therefore large areas of copper are not needed.

0402

0402

0402

0402

0402

0603

0603

REFIN

1

TON

2

REFOUT

3

VCCA

4

FB

5

PGD

6

VSSA

7

PGND

8

DL

9

VDDP

10

ILIM

11

LX

12

DH

13

BST

14

U1

SC1480A

C9

1u

C8

1n

R7

10R

R6

10k0

C2

1u

C10

1u

5VRUN

C7

0u1

.igure 4: Components Connected to VSSA

.igure 5: Example VSSA 0.020” Trace

In .igure 5 above, all components referenced to VSSA have been placed and connected using a 0.020” trace.

Decoupling capacitors C9 and C10 are as close as possible to their pins. C10 should connect to the PGND plane

using two vias.

Application Information (Cont.)