[AK4492]
(2)-2. Auto Setting Mode (AFSD bit= “0”, ACKS bit = “1”)
MCLK frequency and the sampling speed are detected automatically (Table 14) and DFS[2:0] bits are
ignored. The MCLK frequency corresponding to each sampling speed should be provided externally
(Table 15, Table 16).
Table 14. Sampling Speed (Auto Setting Mode)
MCLK
Sampling Speed
1152fs/1024fs
Normal (fs 32kHz)
512fs/256fs 768fs/384fs
Normal
Double
Quad
Oct
256fs
128fs
64fs
384fs
192fs
96fs
32fs
48fs
Hex
Table 15. System Clock Example (Auto Setting Mode)
MCLK (MHz)
LRCK
fs
Sampling
Speed
32fs
N/A
N/A
N/A
N/A
N/A
N/A
N/A
N/A
48fs
N/A
64fs
N/A
96fs
N/A
128fs
N/A
N/A
N/A
N/A
32.0 kHz
44.1 kHz
48.0 kHz
88.2 kHz
96.0 kHz
176.4 kHz
192.0 kHz
384 kHz
768 kHz
N/A
N/A
N/A
Normal
N/A
N/A
N/A
N/A
N/A
N/A
Double
Quad
N/A
N/A
N/A
N/A
N/A
N/A
N/A
22.5792
24.5760
N/A
N/A
N/A
N/A
N/A
36.864
24.576
N/A
36.864
N/A
Oct
Hex
24.576
N/A
(N/A: Not available)
Table 16. System Clock Example (Auto Setting Mode)
MCLK (MHz)
LRCK
Sampling
Speed
fs
192fs
N/A
N/A
N/A
N/A
256fs
8.1920
11.2896
12.2880
22.5792
24.5760
N/A
384fs
12.2880
16.9344
18.4320
33.8688
36.8640
N/A
512fs
16.3840
22.5792
24.5760
N/A
768fs
24.5760
33.8688
36.8640
N/A
1024fs
32.7680
N/A
1152fs
36.8640
N/A
32.0 kHz
44.1 kHz
48.0 kHz
88.2 kHz
96.0 kHz
176.4 kHz
192.0 kHz
384 kHz
768 kHz
Normal
N/A
N/A
N/A
N/A
N/A
N/A
N/A
N/A
N/A
N/A
N/A
N/A
N/A
N/A
Double
Quad
N/A
N/A
N/A
N/A
N/A
N/A
N/A
N/A
N/A
33.8688
36.8640
N/A
N/A
N/A
N/A
N/A
N/A
N/A
Oct
Hex
N/A
N/A
N/A
(N/A: Not available)
When MCLK= 256fs/384fs, auto setting mode supports sampling rate from 8kHz to 96kHz (Table 14).
However, the DR and S/N performances will degrade approximately 3dB as compared to when MCLK =
256fs/384fs for DR and MCLK= 512fs/768fs for S/N, respectively if the sampling rate is under 54kHz.
Table 17. DR and S/N Relationship with MCLK Frequency (fs = 44.1kHz)
ACKS bit
0
MCLK
256fs/384fs/512fs/768fs
256fs/384fs
DR, S/N
123 dB
120 dB
123 dB
1
512fs/768fs
Note 48. This Characteristic is supported by using External Circuit (Figure 74)
016011073-E-00
2016/12
- 44 -
AKM [ ASAHI KASEI MICROSYSTEMS ]
