MOSA

MS6821

4 Stereo inputs / 2W PA output integrated Audio DAC and Volume Control

REV 3

24/29

www.mosanalog.com

Output mode operation -- SE mode and BTL mode

The output mode has two modes, SE mode and BTL mode. The mode is selected by I2C code via a MCU.

In BTL mode, the outputs of A1(B1) and A2(B2) are then used to drive the bridged-tied load

OUTR+

OUTR-

OUTL+

OUTL-

-1

-1

-1

-1

SCL SDA

Interface

R

L

4Ω / 8Ω

R

L

4Ω / 8Ω

A1

A2

B1

B2

In the SE mode, the amplifiers A2 and B2 are shutdown, and then the amplifiers will be a high output impedance state.

OUTR-

OUTL-

-1

-1

-1

-1

SCL SDA

Interface

R

L

16Ω

/ 32Ω

100uF

1k

Headphone

Jack

Shutdown

Shutdown

100uF

1k

A1

A2

B1

B2

Headphone sense

The output mode is SE or BTL that is decided by a headphone. It has to be set SE mode when a headphone is plug-in

status. The output mode is selected by I2C command code by a MCU. Please note that the MS6821 don’t detect a

headphone automatically. Thus a detect function is executed via a MCU. An operation diagram is as follows:

The HP_sense pin is high when a headphone is plug-in.

The HP_sense pin is low when a headphone is not plug-in.