AK4137EQ Datasheet, PDF (44/65 Pages) Asahi Kasei Microsystems – 32bit SRC with PCM/DSD conversion

[AK4137]
■ Dither Circuit
The AK4137 includes a dither circuit. The dither circuit adds a dither signal after the lowest bit of all the
output data set by the OBIT1-0 pins when the DITHER pin = “H”, regardless of SRC and SRC bypass
modes. If the output data has 32-bit length in SRC bypass mode, the output code will not be affected by
the DITHER pin setting. The dither circuit of the AK4137 uses 31-bit maximum length sequence.
■ De-emphasis Filter
In parallel control mode (PSN pin = “H”), de-emphasis setting of the SRC is controlled by DEM1-0
pins. In serial control mode (PSN pin = “L”), the setting of DEM1-0 pins is ignored.
DEM1pin DEM0 pin
Mode
L
L
44.1kHz
L
H
OFF
H
L
48kHz
H
H
32kHz
Table 7. De-emphasis Filter Setting
■ Regulator
The AK4137 has an internal regulator which suppresses the voltage to 1.8V from DVDD. The generated
1.8V power is used as power supply for internal circuits. When an over-current flows into the regulator
output, over-current detection circuit will work. When an over-voltage flows into the regulator output,
over-voltage detection circuit will work. The regulator block is powered-down and the AK4137 becomes
reset state when over-current detection or over-voltage detection is executed. The AK4137 does not
return to normal operation without a reset by the PDN pin when these detection circuits are worked.
When over-current or over-voltage is detected, the PDN pin should be brought into “L” at once, and set
to “H” again to recover normal operation.
The SRCE_N pin indicates the internal status of the device. It outputs “L” in SRC normal operation and
outputs “H” when over-current or over-voltage is detected.
Rev. 0.2
- 44 -
2014/06