AK7735EQ Datasheet, PDF (97/142 Pages) Asahi Kasei Microsystems – Dual DSP with 4chADC + 4chDAC + 4chSRC

[AK7735]
■ ADC Block
1. ADC Block High Pass Filter
The AK7735 has a digital high pass filter (HPF) for DC offset cancelling of each ADC. The cut-off
frequency of the HPF is about 0.9Hz (fs=48kHz), depending on operation frequency.
2. ADC Digital Volume
The AK7735 has independent digital volume controls for Lch and Rch (256 levels, 0.5dB steps) of each
ADC.
ADC1
ADC1
ADC2
ADC2
Attenuation
VOLAD1L[7:0] VOLAD1R[7:0] VOLAD2L[7:0] VOLAD2R[7:0] Level
00h
00h
00h
00h
+24.0dB
01h
01h
01h
01h
+23.5dB
02h
02h
02h
02h
+23.0dB
:
:
:
:
:
2Fh
2Fh
2Fh
2Fh
+0.5dB
30h
30h
30h
30h
0.0dB (default)
31h
31h
31h
31h
-0.5dB
:
:
:
:
:
FDh
FDh
FDh
FDh
-102.5dB
FEh
FEh
FEh
FEh
-103.0dB
FFh
FFh
FFh
FFh
Mute (-∞)
Table 49. ADC Digital Volume Control Setting
The transition time between set values is selected by ATSPAD bit.
Mode ATSPAD bit Transition Time
0
0
4/fs
(default)
1
1
16/fs
Table 50. ADC Volume Level Transition Time
The transition between set values is soft transition. It takes 1020/fs (21.3ms@fs=48kHz) from 00h to
FFh(MUTE) in Mode 0. If the PDN pin goes to “L”, the volume of each ADC channel is initialized to 30h.
ATSPAD bit
0
1
00h ⇔ FFh Transition Time
LRCK Cycle
fs=48kHz fs=44.1kHz fs=8kHz
1020/fs
21.3ms
23.1ms 127.5ms
1020/fs x4
85.0ms
92.5ms 510.0ms
Table 51. ADC Volume Transition Time from 00h to FFh
(default)
016014707-E-00
- 97 -
2016/12