AK4566 Datasheet, PDF (14/45 Pages) Asahi Kasei Microsystems – 20bit Stereo CODEC with built-in IPGA & HP-AMP

ASAHI KASEI
AKM CONFIDENTIAL
[AK4566]
OPERATION OVERVIEW
n System Clock
The external clocks required to operate the AK4566 are MCLK(256fs/384fs/512fs), LRCK(fs) and BICK. The master
clock (MCLK) should be synchronized with sampling clock (LRCK). The phase between these clocks does not matter. The
frequency of MCLK is detected automatically, and the internal master clock becomes the appropriate frequency. Table 1
shows system clock example.
LRCK
fs
8kHz
11.025kHz
12kHz
16kHz
22.05kHz
24kHz
32kHz
44.1kHz
48kHz
MCLK (MHz)
256fs
384fs
512fs
2.048
3.072
4.096
2.8224
3.072
4.2336
4.608
5.6448
6.144
4.096
6.144
8.192
5.6448 8.4672 11.2896
6.144
9.216
12.288
8.192
12.288 16.384
11.2896 16.9344 22.5792
12.288 18.432 24.576
BICK (MHz)
64fs
0.512
0.7056
0.768
1.024
1.4112
1.536
2.048
2.8224
3.072
Table 1. System Clock Example
All external clocks (MCLK, BICK and LRCK) should always be present whenever the ADC or DAC is in normal
operation mode (PMADC bit = “1” or PMDAC bit = “1”). If these clocks are not provided, the AK4566 may draw excess
current and will not operate properly because it utilizes these clocks for internal dynamic refresh of registers. If the external
clocks are not present, ADC and DAC should be placed in the power-down mode (PMADC bit = PMDAC bit = “0”).
When MCLK is input with AC coupling, MCKAC bit should be set to “1”. When MCLK with AC coupling stops, MCKPD
bit should be set to “1”.
When low sampling rate, DR and S/N degrade because of the outband noise. DR and S/N are approved by setting DFS bit
to “1”. Table 2 shows S/N in the case DAC output to HP-amp and MOUT. When DFS bit is “1”, MCLK needs 512fs.
When sampling frequency is changed at normal operation mode of ADC or DAC (PMADC bit = “1” or PMDAC bit = “1”),
DAC output should be soft-muted or “0” data should be input to avoid click noise.
DFS
fs
MCLK
S/N (fs=8kHz, A-weighted)
HP-amp
MOUT
0
8kHz∼48kHz 256fs/384fs/512fs
84dB
84dB
Default
1
8kHz∼24kHz
512fs
90dB
88dB
Table 2. Relationship among fs, MCLK frequency and S/N of HP-amp and MOUT
REV 0.5
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