AK4640VG Asahi Kasei Microsystems, AK4640VG Datasheet - Page 26

• Manufacturer Part Number: AK4640VG
• Description: 16BIT CODEC WITH MIC /HP/SPK-AMPl
• Manufacturer: Asahi Kasei Microsystems

ASAHI KASEI
The S/N of the DAC at low sampling frequencies is worse than at high sampling frequencies due to out-of-band noise.
The out-of-band noise can be improved by using higher frequency of the master clock. The S/N of the DAC output
through Headphone amp at fs=8kHz is shown in Table 11.
The M/S pin selects either master or slave modes. M/S pin = “H” selects master mode and “L” selects slave mode. The
AK4640 outputs MCKO, BICK and LRCK in master mode. The AK4640 outputs only MCKO in slave mode, while
BICK and LRCK must be input separately.
MS0273-E-00
Master Mode/Slave Mode
MCKO pin
BICK pin
LRCK pin
Mode
0
1
2
3
MCKO pin
Table 11. Relationship between MCKI and S/N of HP-AMP
Table 8. MCKO Frequency (EXT Mode, MCKO bit = “1”)
LRCK pin
BICK pin
Master Mode
Slave Mode
Table 9. Clock Operation at Master Mode (EXT Mode)
Table 10. Clock Operation at Slave Mode (EXT Mode)
Mode
Power up
MCKO bit = “0” : “L”
MCKO bit = “1” : Output
Input
Input
1024fs
MCKI
PS1
256fs
512fs
0
0
1
1
Table 12. Master mode/Slave mode
Power up
MCKO bit = “0” : “L”
MCKO bit = “1” : Output
BF bit = “0” : 64fs Output
BF bit = “1” : 32fs Output
Output
MCKO = Output
MCKO = Output
S/N (fs=8kHz, A-weighted)
Master Mode (M/S pin = “H”)
Slave Mode (M/S pin = “L”)
MCKO
PS0
- 26 -
0
1
0
1
84dB
88dB
88dB
Power down
Fixed to “L” or “H” externally
Fixed to “L” or “H” externally
LRCK = Output
BICK = Output
BICK / LRCK
LRCK = Input
MCKO
BICK = Input
256fs
128fs
64fs
32fs
Power down
“L”
“L”
“L”
“L”
Default
[AK4640]
2004/03