AK5701_07 Datasheet, PDF (33/64 Pages) Asahi Kasei Microsystems – 16-Bit ΔΣ Stereo ADC with PLL & MIC-AMP

[AK5701]
■ Digital High Pass Filter
The ADC has a digital high pass filter for DC offset cancellation. The cut-off frequency of the HPF is selected by HPF1-0
bits (Table 18) and scales with sampling rate (fs). The default value is 3.4Hz (@fs=44.1kHz).
HPF1 bit
0
0
1
1
HPF0 bit
fs=44.1kHz
fc
fs=22.05kHz
fs=11.025kHz
0
3.4Hz
1.7Hz
0.85Hz
1
6.8Hz
3.4Hz
1.7Hz
0
13.6Hz
6.8Hz
3.4Hz
1
N/A
N/A
N/A
Table 18. Digital HPF Cut-off Frequency (N/A: Not available)
(default)
■ MIC/LINE Input Selector
The AK5701 has input selector. When MDIF1 and MDIF2 bits are “0”, INL and INR bits select LIN1/LIN2 and
RIN1/RIN2, respectively. When MDIF1 and MDIF2 bits are “1”, LIN1, RIN1, LIN2 and RIN2 pins become LIN+, LIN−,
RIN− and RIN+ pins respectively. In this case, full-differential input is available (Figure 37).
MDIF1 bit
0
1
MDIF2 bit
INL bit
INR bit
Lch
0
0
LIN1
0
1
LIN1
1
0
LIN2
1
LIN2
1
0
x
LIN1
1
x
N/A
0
x
0
N/A
1
LIN+/−
1
x
x
LIN+/−
Table 19. MIC/Line In Path Select (N/A: Not available)
Rch
RIN1
RIN2
RIN1
RIN2
RIN+/−
N/A
N/A
RIN2
RIN+/−
(default)
AK5701
LIN1/LIN+ pin
RIN1/ LIN− pin
INL bit
MDIF1 bit
ADC Lch
RIN2/ RIN+ pin
LIN2/ RIN− pin
INR bit
MDIF2 bit
ADC Rch
Figure 36. Mic/Line Input Selector
MS0404-E-02
- 33 -
2007/08