Technical Note

8/16

BD5461GUL

www.rohm.com

2010.06 - Rev.A

© 2010 ROHM Co., Ltd. All rights reserved.

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The way of evaluating Audio characteristic

Evaluation Circuit Diagram

When measuring Audio characteristics, insert LC filter during the output terminal of IC and the speaker load and measure it.

Arrange LC filter as close as possible to the output terminal of IC.

In case of L=22μH, C=1μF, the cutoff frequency becomes the following.

Use a big current type - Inductor L.

(Reference)

TDK: SLF12575T-220M4R0

STBY

IN+

IN-

OUT-

OUT+

Bias

OSC

PWM

H-

Bridge

0.1μ

0.1μ

Differential

Input

H：Active

L：Shutdown

Audio

Input+

Audio

Input-

GND

PGND

VDD

PVDD

10μ

C2

A1

C1

A3

C3

0.1μ

VDD

VDD

C2

C1

C3

A2

B3

C4

B1

300k

B2

Ri=75k

Ri=75k

22μH

22μH

1μF

1μF

Audio

Precision

etc

RL=Speaker Load

Measument Instrumen

+

-

kHz

34

μF

1

μH

22

π

2

1

LC

π

2

1

fc







