AK7735EQ Datasheet, PDF (100/142 Pages) Asahi Kasei Microsystems – Dual DSP with 4chADC + 4chDAC + 4chSRC

[AK7735]
4-1. Input Selector Switching Sequence
The input selector should be changed after enabling soft mute function to avoid the switching noise of
the input selector.
ADC2 Input selector switching sequence:
1) Enable Soft Mute Function before Changing Channel
2) Change Channel
3) Disable Soft Mute Function
AD2MUTE bit
(2)
DATT Level
(1)
(1)
Attenuation
(3)
-∞
Channel
IN3L/IN3R
IN4L/IN4R
Figure 74. ADC2 Input Channel Switching Sequence Example
The period of (1) varies according to the setting value of the DATT level. Transition time of attenuation
level from 0dB to - is shown below.
ATSPAD bit
LRCK Cycle
(1) Period (Max)
fs=48kHz fs=44.1kHz fs=8kHz
0
828/fs
17.25ms
18.78ms 103.5ms (default)
1
828/fs x 4
69ms
75.10ms 414ms
The input channel should be changed during the period (2). An interval around 200ms is needed before
releasing the soft mute after changing the channel (period (3)).
5. ADC Digital Filter Select
The AK7735 has four kinds of digital filters in ADC block. ADSD and ADSL bits select a digital filter.
ADC1 and ADC2 have a common setting for digital filter.
Mode
0
1
2
3
ADSD bit
0
0
1
1
ADSL bit
Digital Filter
0
Sharp Roll-Off Filter
1
Slow Roll-Off Filter
0
Short Delay Sharp Roll-Off Filter
1
Short Delay Slow Roll-Off Filter
Table 54. ADC Digital Filter Select
(default)
016014707-E-00
- 100 -
2016/12