AK4953A Datasheet, PDF (39/96 Pages) Asahi Kasei Microsystems – 24bit Stereo CODEC with MIC/HP/SPK-AMP

[AK4953A]
Mode
ADCPF bit PFDAC bit
Recording Mode 1
1
0
Playback Mode 1
0
1
Recording Mode 2 & Playback Mode 2
(Programmable Filter Bypass Mode: PMPFIL bit = “0”)
x
0
Loopback Mode
1
1
Table 25. Recording Playback Mode (x: Don’t care)
PFSDO bit
1
0
0
1
Figure
Figure 31
Figure 32
Figure 33
Figure 34
LPF bit, HPF bit, EQ0 bit, EQ1 bit, EQ2 bit, EQ3 bit, EQ4 bit, EQ5 bit, ACL1 bit and ALC2 bit must be “0” when
changing those modes.
ADC
1st Order
HPF1
1st Order
HPF2
1st Order
LPF
4 Band
EQ
ALC
(Volume)
1 Band
EQ
DAC
ADC
SMUTE DVL/R
Figure 31. Path at Recording Mode 1 (default)
1st Order
HPF1
DAC
SMUTE DVL/R
1 Band
EQ
ALC
(Volume)
4 Band
EQ
Figure 32. Path at Playback Mode 1
ADC
1st Order
HPF1
1st Order
LPF
1st Order
HPF2
DAC
ADC
SMUTE DVL/R
Figure 33. Path at Recording Mode 2 & Playback Mode 2
1st Order
HPF1
1st Order
HPF2
1st Order
LPF
4 Band
EQ
ALC
(Volume)
1 Band
EQ
DAC
SMUTE DVL/R
Figure 34. Path at Loopback Mode
■ Digital HPF1
A digital High Pass Filter (HPF) is integrated for DC offset cancellation of the ADC input. The cut-off frequencies of the
HPF1 are set by HPFC1-0 bits (Table 26). It is proportional to the sampling frequency (fs) and default is 3.4Hz (@fs =
44.1kHz). HPFAD bit controls the ON/OFF of the HPF1 (HPF ON is recommended).
HPFC1 bit HPFC0 bit
0
0
0
1
1
0
1
1
fc
fs=96kHz fs=44.1kHz fs=22.05kHz
7.4Hz
3.4Hz
1.7Hz
29.6Hz
13.6Hz
6.8Hz
236.8Hz
108.8Hz
54.4Hz
473.6Hz
217.6Hz
108.8Hz
Table 26. HPF1 Cut-off Frequency
fs=8kHz
0.62Hz
2.47Hz
19.7Hz
39.5Hz
(default)
MS1252-E-00
- 39 -
2010/10