AK5730 Datasheet, PDF (26/50 Pages) Asahi Kasei Microsystems – 4-Channel Differential Audio ADC for Line & Mic Inputs

[AK5730]
■ System Reset
The AK5730 should be reset once by bringing the PDN pin = “L” upon power-up. The AK5730 is powered up and the
internal timing starts clocking by LRCK “↑” after exiting the power down state of reference voltage (such as VCOM) by
MCLK. In slave mode, the AK5730 is in power-down mode until MCLK and LRCK are input. In master mode, the
AK5730 is in power-down mode until MCLK is input. Following all clock inputs, set RSTN bit to “1” after setting
microphone bias voltage (MBS3-0 bits).
■ Digital Attenuator
The AK5730 has a channel-independent digital attenuator (256 levels, 0.5dB step). Attenuation level of each channel can
be set by each the ATT7-0 bits (Table 7).
ATT7-0
00H
01H
:
FEH
FFH
Attenuation Level
+12dB
+11.5dB
:
0dB(default)
-0.5dB
-1.0dB
:
-115.0dB
MUTE (-∞)
Table 7. Attenuation level of digital attenuator
Transition time between set values of ATT7-0 bits can be selected by ATS1-0 bits (Table 8). Transition between set
values is the soft transition in Mode1/2/3 eliminating a switching noise in the transition.
Mode
0
1
2
3
ATS1
0
0
1
1
ATS0
0
1
0
1
ATT speed
3712/fs
928/fs
1856/fs
7424/fs
(default)
Table 8. Transition Time between Set Values of ATT7-0 bits
The transition between set values is a soft transition of 3712 levels in mode 0. It takes 3712/fs (77.3ms@fs=48kHz) from
00H(0dB) to FFH(MUTE). If the PDN pin goes to “L”, the ATTs are initialized to 00H. The ATTs also become 00H
when RSTN bit = “0”, and fade to their current value when RSTN bit returns to “1”.
Rev 0.8
- 26 -
2013/06