ak4635ecb AKM Semiconductor, Inc., ak4635ecb Datasheet - Page 31

• Manufacturer Part Number: ak4635ecb
• Description: 16-bit Mono Codec With Alc & Mic/spk/video-amp
• Manufacturer: AKM Semiconductor, Inc.

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When PMPLL bit is “0”, the AK4635 becomes EXT Slave 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
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 is not important. The input frequency of MCKI is selected by FS1-0 bits.
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.The
out-of-band noise can be improved by using higher frequency of the master clock.
The external clocks (MCKI, BICK and FCK) should always be present whenever the ADC or DAC or SPK or
Programmable Filter is in operation (PMADC = PMDAC = PMSPK bit = PMPFIL bits = “1”). If these clocks are not
provided, the AK4635 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, SPK and Programmable Filter should be
in the power-down mode (PMADC = PMDAC = PMSPK bit = PMPFIL bits = “0”).
Rev. 0.6
EXT Slave Mode (PMPLL bit = “0”, M/S bit = “0”)
Mode
0
1
2
3
Table 11. MCKI Frequency at EXT Slave Mode (PMPLL bit = “0”, M/S bit = “0”) (x: Don’t care)
FS3-2 bits
Table 13. Relationship between MCKI and Output Noise Level of SPK-Amp
Table 12. Relationship between MCKI and S/N of AOUT and SPK-Amp
x
x
x
x
1024fs
1024fs
MCKI
MCKI
256fs
512fs
256fs
512fs
AK4635
FS1 bit
MCKO
MCKI
BICK
FCK
SDTO
SDTI
0
0
1
1
(SVDD=3.3V,fs=8kHz, 20kHzLPF + A-weighted)
S/N (fs=8kHz, 20kHzLPF + A-weighted)
Figure 27. EXT Slave Mode
FS0 bit
256fs, 512fs or 1024fs
0
1
0
1
SDTI
- 31 -
Output Noise Level
1fs
DAC
32fs
MCKI Input
-73dBV
-86dBV
-88dBV
Frequency
84dB
92dB
92dB
1024fs
256fs
512fs
256fs
SPK-Amp
AOUT
MCLK
BCLK
FCK
SDTI
SDTO
DSP or P
7.35kHz
7.35kHz
7.35kHz
7.35kHz
Sampling Frequency
(Table
Range
12,
fs
fs
fs
fs
Table
48kHz
13kHz
26kHz
48kHz
13)
(default)
(Table
[AK4635]
2007/10
11)