AK5374 Datasheet, PDF (16/51 Pages) Asahi Kasei Microsystems – 24-bit Stereo ADC with USB Interface

[AK5374]
■ Volume & Mute Control
The AK5374 has a digital volume control which ranges from +24dB to -31dB in 1dB step. The maximum volume, the
minimum and default volumes are defined by EEP-ROM header setting.
When ZCE bit = “1” (Zero cross detection enable), L-channel and R-channel volumes are changed independently on zero
cross or zero cross timeout. Zero cross timeout is set by ZTM1-0 bits (Table 7). When ZCE bit = “0” (zero cross detection
disable), the volume is changed immediately. Mute operation and zero cross detection have the same relation as the
volume mentioned in this section.
ZTM1
bit
0
0
1
1
ZTM0
bit
0
1
0
1
Zero Crossing Timeout Period
8kHz
16kHz
44.1kHz
128/fs
16ms
8ms
2.9ms
256/fs
32ms
16ms
5.8ms
512/fs
64ms
32ms
11.6ms
1024/fs
128ms
64ms
23.2ms
Table 7. Zero Crossing Timeout Period
The AK3573 has the LMUTEN and RMUTEN pins. and they can control mute operations from the device side. However,
because the AK5374 does not have HID function, the mute operation by these pins cannot be acknowledged by the host.
There are two modes for the mute operation by LMUTEN and RMUTEN pins; one is normal mute and the other is
one-shot mute.
In normal mute operation (OSME bit = “0”), mute is executed on zero cross or zero cross timeout when the LMUTEN and
RMUTEN pins = “L” if zero cross detection is enabled. When zero cross detection is disabled, it is executed immediately.
In case that the LMUTEN and RMUTEN pins = “H”, mute is released on zero cross or zero cross timeout if the zero cross
detection is enabled. When zero cross detection is disabled, it is released immediately.
LMUTEN pin
RMUTEN pin
AD data
Zero cross
Set Value
Volume
(ZCE bit = “1”)
-∞
Set Value
Volume
(ZCE bit = “0”)
-∞
Figure 13. Normal Mute for LMUTEN, RMUTEN pins
MS1197-E-00
- 16 -
2010/05