AK5538VN Datasheet, PDF (53/70 Pages) Asahi Kasei Microsystems – 8-Channel Differential 32-bit ADC

[AK5538]
■ Digital Filter Setting (PCM Mode)
The AK5538 has four types of digital filters and they can be selected by SD pin (bit) and SLOW pin (bit).
The filter setting is not available in OCT speed mode, HEX speed mode and DSD mode. So the setting of
the digital filter is ignored.
SD pin (bit)
L (0)
L (0)
H (1)
H (1)
SLOW pin (bit)
Filter
L (0)
Sharp Roll-off Filter
H (1)
Slow Roll-off Filter
L (0)
Short Delay Sharp Roll-off Filter
H (1)
Short Delay Slow Roll-off Filter
Table 20. Digital Filter Setting
■ Digital HPF (PCM Mode)
The AK5538 has a digital high-pass filter for DC offset (include internal offset) cancelation. The digital
high-pass filter is enabled by setting the HPFE pin (bit) = “H (1)”. The cut-off frequency of the high-pass
filter is fixed 1.0 Hz when fs= 48 kHz (Normal Speed mode), 96 kHz (Double Speed mode) or 192 kHz
(Quad Speed mode). The high-pass filter is not available in OCT speed mode, HEX speed mode and
DSD mode. So that the setting of the HPFE pin is ignored. The high pass-filter setting should be changed
when all channels are reset condition.
■ Overflow Detection (PCM Mode, DSD Mode)
[1] PCM Mode
The AK5538 has an overflow detect function for the analog input.
The OVF pin outputs “H” if one of AIN1 - 8 channels overflows (more than 0.3 dBFS). The OVF pin
returns to “L” when analog input overflows are resolved. The OVF output for overflowed analog input has
the same group delay as the ADC.
[2] DSD Mode
Overflow Detection (Error Detection Function)
The OVF pin outputs “H” if any channel’s DSD modulators overflows. The OVF pin returns to “L” when
overflows are resolved.
015099878-E-00
- 53 -
2016/03