AK4633 Datasheet, PDF (31/82 Pages) Asahi Kasei Microsystems – 16-Bit Mono CODEC with ALC & MIC/SPK-AMP

ASAHI KASEI
[AK4633]
„ EXT Slave Mode (PMPLL bit = “0”, M/S bit = “0”)
When PMPLL bit is “0” and M/S bit is “0”, the AK4633 becomes EXT slave 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), BICK (≥32fs) and FCK (fs). 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 ( Table 11).
Mode
0
1
2
3
FS3-2 bits
FS1 bit FS0 bit MCKI Input Sampling Frequency
Frequency
Range
Don’t care
0
0
256fs
7.35kHz ≤ fs ≤ 48kHz Default
Don’t care
0
1
1024fs
7.35kHz < fs ≤ 13kHz
Don’t care
1
0
512s
7.35kHz < fs ≤ 26kHz
Don’t care
1
1
256fs
7.35kHz < fs ≤ 48kHz
Table 11. Setting MCKI Frequency at EXT Slave Mode (PMPLL bit = “0”, M/S bit = “0”)
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 12.
MCKI
S/N
(fs=8kHz, 20kHzLPF + A-weighted)
256fs
84dB
512fs
92dB
1024fs
92dB
Table 12. Relationship between MCKI and S/N of AOUT
The external clocks (MCKI, BICK and FCK) should always be present whenever the ADC or DAC or Programmable
Filter are in operation (PMADC bit = “1” or PMDAC bit = “1” or PMPFIL bit = “1”). If these clocks are not provided, the
AK4633 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, DAC and Programmable Filter should be in the power-down
mode (PMADC bit =PMDAC bit = PMPFIL bit = “0”).
AK4633
MCKO
MCKI
BICK
FCK
SDTO
SDTI
256fs, 512fs or 1024fs
DSP or µP
MCLK
32fs, 64fs
BCLK
1fs
FCK
SDTI
SDTO
Figure 21. EXT Slave Mode
MS0447-E-03
- 31 -
2006/04