ak4566vn AKM Semiconductor, Inc., ak4566vn Datasheet - Page 14

• Manufacturer Part Number: ak4566vn
• Description: 20bit Stereo Codec With Built-in Ipga & Hp-amp
• Manufacturer: AKM Semiconductor, Inc.

ASAHI KASEI
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.
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.
REV 0.5
DFS
0
1
Table 2. Relationship among fs, MCLK frequency and S/N of HP-amp and MOUT
8kHz 48kHz
8kHz 24kHz
11.025kHz
22.05kHz
44.1kHz
LRCK
12kHz
16kHz
24kHz
32kHz
48kHz
8kHz
fs
fs
11.2896
256fs/384fs/512fs
2.8224
5.6448
12.288
256fs
2.048
3.072
4.096
6.144
8.192
Table 1. System Clock Example
OPERATION OVERVIEW
AKM CONFIDENTIAL
MCLK
512fs
MCLK (MHz)
16.9344
4.2336
8.4672
12.288
18.432
384fs
3.072
4.608
6.144
9.216
- 14 -
S/N (fs=8kHz, A-weighted)
HP-amp
11.2896
22.5792
84dB
90dB
5.6448
12.288
16.384
24.576
512fs
4.096
6.144
8.192
BICK (MHz)
MOUT
84dB
88dB
0.7056
1.4112
2.8224
0.512
0.768
1.024
1.536
2.048
3.072
64fs
Default
[AK4566]
2002/2