AK5700 Datasheet, PDF (38/61 Pages) Asahi Kasei Microsystems – 16-Bit ΔΣ Mono ADC with PLL & MIC-AMP

ASAHI KASEI
[AK5700]
When writing to the IVL7-0 bits continuouslly, the control register should be written by an interval more than zero
crossing timeout. If not, IVL is not changed since zero crossing counter is reset at every write operation. If the same
register value as the previous write operation is written to IVL, this write operation is ignored and zero crossing counter is
not reset. Therefore, IVL can be written by an interval less than zero crossing timeout.
ALC bit
ALC Status
Disable
Enable
Disable
IVL7-0 bits
Internal IVL
E1H(+30dB)
E1H(+30dB)
(1)
E1(+30dB) --> F1(+36dB)
(2)
E1(+30dB)
Figure 36. IVOL value during ALC operation
(1) The wait time from ALC bit = “1” to ALC operation start by IVL7-0 bits is at most recovery time (WTM1-0 bits) plus
zerocross timeout period (ZTM1-0 bits).
(2) Writing to IVL register (18H) is ignored during ALC operation. After ALC is disabled, the IVOL changes to the last
written data by zero crossing or timeout. When ALC is enabled again, ALC bit should be set to “1” by an interval
more than zero crossing timeout period after ALC bit = “0”.
„ System Reset
Upon power-up, the AK5700 should be reset by bringing the PDN pin = “L”. This ensures that all internal registers reset
to their initial values.
The ADC enters an initialization cycle that starts when the PMADC bit is changed from “0” to “1”. The initialization
cycle time is 3088/fs=70.0ms@fs=44.1kHz when HPF1-0 bits are “00” (see Table 30). During the initialization cycle, the
ADC digital data outputs of both channels are forced to a 2’s complement, “0”. The ADC output reflects the analog input
signal after the initialization cycle is complete.
HPF1 bit
0
0
1
1
HPF0 bit
0
1
0
1
Cycle
3088/fs
1552/fs
Init Cycle
fs=44.1kHz
fs=22.05kHz
70.0ms
(Recommendation)
140.0ms
35.2ms
70.4ms
(Recommendation)
784/fs
17.8ms
35.6ms
N/A
N/A
N/A
Table 30. ADC Initialization Cycle
fs=11.025kHz
280.1ms
140.8ms
71.1ms
(Recommendation)
N/A
Default
MS0569-E-01
- 38 -
2006/12