AK4646EN AKM [Asahi Kasei Microsystems], AK4646EN Datasheet - Page 25

• Manufacturer Part Number: AK4646EN
• Description: Stereo CODEC with MIC/SPK-AMP
• Manufacturer: AKM [Asahi Kasei Microsystems]

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When PMPLL bit is “0”, the AK4646 becomes EXT mode. Master clock can directly be inputted from MCKI pin, without
the internal PLL circuit operation. This mode is compatible with I/F of the normal audio CODEC. The clocks required to
operate this mode are MCKI (256fs, 512fs or 1024fs), LRCK (fs) and BICK (≥32fs). The master clock (MCKI) should be
synchronized with LRCK. The phase between these clocks does not matter. The input frequency of MCKI is selected by
FS1-0 bits (Table 11).
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 LOUT/ROUT pins at fs=8kHz is shown in Table 12.
The external clocks (MCKI, BICK and LRCK) should always be present whenever the ADC or DAC is in operation
(PMADL bit = “1”, PMADR bit = “1” or PMDAC bit = “1”). If these clocks are not provided, the AK4646 may draw
excess current and it is not possible to operate properly because utilizes dynamic refreshed logic internally. When the
external clocks are not present, the ADC and DAC should be in the power-down mode (PMADL=PMADR=PMDAC bits
= “0”).
MS0557-E-02
EXT Slave Mode (PMPLL bit = “0”, M/S bit = “0”)
Others
Mode
0
1
2
3
Table 11. 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 12. Relationship between MCKI and S/N of LOUT/ROUT pins
AK4646
Others
1024fs
MCKI
FS1 bit
256fs
512fs
MCKO
MCKI
BICK
LRCK
SDTO
SDTI
0
0
1
1
Figure 16. EXT Slave Mode
(fs=8kHz, 20kHzLPF + A-weighted)
FS0 bit
256fs, 512fs or 1024fs
0
1
0
1
- 25 -
≥ 32fs
1fs
MCKI Input
83dB
93dB
93dB
Frequency
S/N
1024fs
256fs
512fs
256fs
N/A
MCLK
BCLK
LRCK
SDTI
SDTO
DSP or μP
Sampling Frequency
7.35kHz ∼ 48kHz
7.35kHz ∼ 13kHz
7.35kHz ∼ 26kHz
7.35kHz ∼ 48kHz
Range
N/A
(default)
[AK4646]
2007/05