AK4558EN Datasheet, PDF (48/94 Pages) Asahi Kasei Microsystems – 108dB 216kHz 32Bit CODEC with PLL

[AK4558]
■ De-emphasis Filter
DEM1-0 bits control a digital de-emphasis filter for DAC (SDTI) inputs. This filter (tc=50/15s) is
composed by IIR filter and corresponds to three frequencies (32kHz, 44.1kHz, 48kHz). It is always OFF
in double and quad speed modes.
Mode
0
1
2
3
4
5
Sampling Speed Mode DEM1
DEM0
DEM
Normal Speed Mode
0
0
44.1kHz
Normal Speed Mode
0
1
OFF
Normal Speed Mode
1
0
48kHz
Normal Speed Mode
1
1
32kHz
Double Speed Mode Don’t Care Don’t Care
OFF
Quad Speed Mode
Don’t Care Don’t Care
OFF
Table 22. De-emphasis Filter Control
(default)
■ Digital HPF
The ADC has a Digital High Pass Filter (HPF) for DC-offset cancellation. The cut-off frequency of the
HPF is 1Hz at fs=48kHz and the frequency response at 20Hz is -0.12dB. It also scales with the sampling
frequency (fs). The HPF is controlled by CKS3-0 pins (Table 7). If the HPF setting (ON/OFF) is changed
in operation, click noise occurs by changing DC offset. It is recommended to change HPF setting during
power-down state (PDN pin = “L”).
When the PS pin = “L”, L and R channel HPFs can be ON/OFF independently by HPFEL and HPFER
bits, respectively.
015004500-E-02
- 48 -
2015/09