ak4632 AKM Semiconductor, Inc., ak4632 Datasheet - Page 26

• Manufacturer Part Number: ak4632
• Description: 16-bit ?? Mono Codec With Alc & Mic/spk/video-amp
• Manufacturer: AKM Semiconductor, Inc.

ASAHI KASEI
When PMPLL bit is “0”, the AK4632 becomes EXT mode. Master clock is input from MCKI pin, the internal PLL circuit
is not operated. This mode is compatible with I/F of the normal audio CODEC. The clocks required to operate are MCKI
(256fs, 512fs or 1024fs), FCK (fs) and BICK (32fs∼). The master clock (MCKI) should be synchronized with FCK. The
phase between these clocks does not matter. The input frequency of MCKI is selected by FS3-0 bits. (See Table 10)
External Slave Mode does not support Mode 0 (DSP Mode) of Audio Interface Format.
The S/N of the DAC at low sampling frequencies is worse than at high sampling frequencies due to out-of-band noise.
When the out-of-band noise can be improved by using higher frequency of the master clock. The S/N of the DAC output
through AOUT amp at fs=8kHz is shown in Table 11.
The external clocks (MCKI, BICK and FCK) should always be present whenever the ADC or DAC is in operation
(PMADC bit = “1” or PMDAC bit = “1”). If these clocks are not provided, the AK4632 may draw excess current and it is
not possible to operate properly because utilizes dynamic refreshed logic internally. If the external clocks are not present,
the ADC and DAC should be in the power-down mode (PMADC bit = PMDAC bit = “0”).
MS0396-E-00
EXT Slave Mode (PMPLL bit = “0”, M/S bit = “0”)
Mode
0
1
2
3
Table 10. MCKI Frequency at EXT Slave Mode (PMPLL bit = “0”, M/S bit = “0”)
FS3-2 bits
Don’t care
Don’t care
Don’t care
Don’t care
Table 11. Relationship between MCKI and S/N of AOUT
AK4632
1024fs
FS1 bit
MCKI
256fs
512fs
MCKO
MCKI
BICK
FCK
SDTO
SDTI
0
0
1
1
Figure 22. EXT Slave Mode
(fs=8kHz, 20kHzLPF + A-weight)
FS0 bit
256fs, 512fs or 1024fs
0
1
0
1
32fs, 64fs
- 26 -
1fs
MCKI Input
83dB
93dB
93dB
S/N
Frequency
1024fs
256fs
256fs
512fs
MCLK
BCLK
FCK
SDTI
SDTO
DSP or µ P
7.35kHz ≤ fs ≤ 48kHz
7.35kHz < fs ≤ 13kHz
7.35kHz < fs ≤ 48kHz
7.35kHz < fs ≤ 26kHz
Sampling Frequency
Range
Default
[AK4632]
2005/06