ak4671 AKM Semiconductor, Inc., ak4671 Datasheet - Page 49

• Manufacturer Part Number: ak4671
• Description: Stereo Codec With Mic/rcv/hp-amp
• Manufacturer: AKM Semiconductor, Inc.

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When PMPLL bit is “0”, the AK4671 becomes EXT mode. Master clock is input from the 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 the
AK4671 are MCKI (256fs, 384fs, 512fs, 768fs 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 FS2-0 bits
In case that the CODEC is used without Audio I/F (like phone call), the CODEC can be operated by MCKI only. In this
case, BICK and LRCK can be stopped.
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 reduced 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
MCKI should always be present whenever the ADC or DAC is in operation (PMADL bit = “1”, PMADR bit = “1”,
PMDAL bit = “1” or PMDAR bit = “1”). If MCKI is not provided, the AK4671 may draw excess current and it is not
possible to operate properly because utilizes dynamic refreshed logic internally. If MCKI is not present, the ADC and
DAC should be in the power-down mode (PMADL=PMADR=PMDAL=PMDAR bits = “0”).
MS0666-E-00
Others
EXT Slave Mode (PMPLL bit = “0”, M/S bit = “0”)
Mode
0
1
4
5
6
7
FS3 bit
Others
x
x
x
x
x
x
Table 11. MCKI Frequency at EXT Slave Mode (PMPLL bit = “0”, M/S bit = “0”)
(Table
Table 12. Relationship between MCKI and S/N of LOUT1/ROUT1 pins
FS2 bit
11).
0
0
1
1
1
1
AK4671
256fs, 384fs
512fs, 768fs
1024fs
MCKI
MCKO
MCKI
BICK
LRCK
SDTO
SDTI
FS1 bit
0
0
0
0
1
1
Table
Figure 43. EXT Slave Mode
12.
(fs=8kHz, 20kHzLPF + A-weighted)
FS0 bit
256fs, 384fs, 512fs,
768fs or 1024fs
0
1
0
1
0
1
- 49 -
≥ 32fs
1fs
83dB
93dB
93dB
MCKI Input
S/N
Frequency
1024fs
256fs
384fs
768fs
512fs
256fs
N/A
(x: Don’t care, N/A: Not available)
MCLK
BCLK
LRCK
SDTI
SDTO
DSP or μP
Sampling Frequency
8kHz ∼ 48kHz
8kHz ∼ 13kHz
8kHz ∼ 48kHz
8kHz ∼ 26kHz
8kHz ∼ 26kHz
8kHz ∼ 48kHz
Range
N/A
(default)
[AK4671]
2007/10