Technical Note

11/16

www.rohm.com

2010.09 - Rev.A

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

BU7831KN

●

Recommended operation sequence

VDD ON

NRST=L start. Rise up VDD first.

After the mode setting, input the audio signal.

Fig. 30

VDD OFF

HPRST=0(82h=00h) is taken at the time of use of HPAMP first.

VDD OFF, after the mute on setting(88h=FFh), NRST=L at using HPAMP.

VDD OFF, after NRST=L at not using HPAMP.

Fig. 31

HPAMP ON

Mute OFF (HPRST 82h bit0), after the mode setting.

Fig. 32

・

HPAMP OUTPUT rise time setting up expression

Thpout = 80.6 × 10

・

HSMUTE delay time setting up expression

Thsmute = 200 × 10

CPU I/F

Audio Signal

Analog Signal

Mode Set

NRST

VDD

VDD

ATT6L,R(88h)

NRST

Headphone output

00h

01h

FFh

XXh

HPRST(82h)

HPRST (82h bit0)

Headphone output(DC)

CPU I/F

Mode Set

Thpout

Thsmute