BD9853AFV

Technical Note

13/16

www.rohm.com

2009.05 - Rev.A

© 2009 ROHM Co., Ltd. All rights reserved.

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Recommended Board Patterns

There are two current loops at the behavior of switching regulator. When laying a pattern on the board, put these elements

near to minimize these current loops and make the lines as short and wide as possible. And connect all GND lines at one

point to reduce effects caused by above current noise to other lines.

a pattern example of switching part

Place following parts with attention about patterns

・

Place CVCC, CREGA, RRT, CREGB as near to the pin as possible.

・

Pattern area has to be small enough to reduce parasitic capacitance with RT terminal.

C

IN

P

MOS

SBD

L

INV

GND(IC)

GND(others)

VOUT

1

2

3

4

5

6

7

8

10

9

11

12

13

14

15

16

VCC

REGA

RT

REGB

CREGB

CVCC

CREGA

RRT

GND

GND

VCC

REGB

L

SBD