[AK4675]
■ System Clock (PCM I/F)
A reference clock of PLLBT is selected among the input clocks to the SYNCA, BICKA, SYNCB or BICKB pin. The
required clock to PCM I/F is generated by an internal PLLBT circuit. PLLBT circuit is powered up by PMPCM bit. Input
frequency is selected by PLLBT3-0 bits (Table 95). BCKO2 bit select the output clock frequency of the BICKA or
BICKB pin (Table 96).
The AK4675 does not support master mode for both PCM I/F A and B nor slave mode for both PCM I/F A and B.
Whether PCM I/F A or B should be set as slave mode. When PMPCM bit is “0”, SYNCA, BICKA, SYNCB and BICKB
pins are Hi-Z. Table 97 indicates the output data of the SDTOA and SDTOB pins in case of PMPCM bit = “0” and during
lock time in Table 95, respectively. Table 98 indicates the output clock at master mode during lock time in Table 95.
The AK4675 does not support master mode for both PCM I/F A and B nor slave mode for both PCM I/F A and B. When
PMPCM bit is “0”, the SYNCA, BICKA, SYNCB and BICKB pins are Hi-Z.
R, C at
VCOCBT pin
Reference Clock
Input Pin
Lock Time
(max)
Mode
PLLBT3 PLLBT2 PLLBT1 PLLBT0
Frequency
R
C
0
1
2
3
4
5
6
7
11
0
0
0
0
0
0
0
0
1
1
0
0
0
0
1
1
1
1
0
1
0
0
1
1
0
0
1
1
1
1
0
1
0
1
0
1
0
1
1
1
SYNCA
BICKA
BICKA
BICKA
SYNCB
BICKB
BICKB
BICKB
BICKA
BICKB
N/A
1fs2
16fs2
32fs2
64fs2
1fs2
16fs2
32fs2
64fs2
48fs2
48fs2
6.8k
10k
10k
10k
6.8k
10k
10k
10k
10k
10k
220n
4.7n
4.7n
4.7n
220n
4.7n
4.7n
4.7n
4.7n
4.7n
260ms
40ms
40ms
40ms
260ms
40ms
40ms
40ms
40ms
40ms
(default)
15
Others
Note 83. Mode 1 is available at only FMTA1 bit = “0”.
Note 84. Mode 5 is available at only FMTB1 bit = “0”.
Table 95. PLLBT Reference Clock
BICKA/BICKB
Output Frequency
16fs2
BCKO2 bit
0
1
(default)
32fs2
Table 96. BICKA/B Output Frequency
PMPCM bit = “1”
During Lock time
After PMPCM bit = “0” → “1”
& Before SYNCA/SYNCB Input
Mode
PMPCM bit = “0”
16bit Linear
8bit A-Law
8bit μ-Law
L
L
L
L
H
H
“0000H”
“11010101b”
“11111111b”
Table 97. SDTOA, SDTOB pins Output Data
Format
SYNCA, SYNCB
BICKA, BICKB
Except for I2S
I2S
L
H
L
L
Table 98. Output Clock during Lock Time
MS0963-E-00
2008/05
- 123 -
AKM [ ASAHI KASEI MICROSYSTEMS ]
