AK4560A Datasheet, PDF (31/47 Pages) Asahi Kasei Microsystems – 16bit CODEC with ALC and MIC/HP/SPK-Amps

ASAHI KASEI
[AK4560A]
n Analog Volume (OPGA)
The AK4560A includes the 0dB ∼ -50dB & MUTE analog volume with zero crossing detection for headphone and
speaker. Zero crossing is detected on L/R channels independently. Zero crossing timeout (To) is proportional to sampling
rate. To=512/fs@fs=48kHz=10.7ms.
OPGA is not written during counting zero crossing timers. In case of writing control register continually, the change of
OPGA should be written after zero crossing timeout and over. If OPGA is changed by writing to control register before
zero crossing detection, OPGA value of L/R channels may not give a difference level.
Usually, to remove the offset of DAC, it needs a capacitor (Ca) between LOUT2/ROUT2 and OPGL/OPGR. The cut-off
frequency is decided by capacity of Ca and input impedance (typ. 110k Ω) of OPGL/OPGR.
Power supply for analog volume enables when speaker or headphone of power management bits is “1”. (SPKP bit = “1”
or HPP bit = “1”)
The initial value is 0dB at exiting power-down.
LOUT2/ROUT2 Ca
typ.110kΩ _OPGA
OPGL/OPGR
n LINE input
Figure 17. Connect LOUT2/ROUT2 with OPGL/OPGR
In case of LINE input, input impedance of LIN/RIN is 184kΩ (typ.) and centered around the VCOM voltage. When input
voltage is +2dBV, LIN/RIN pins should be input to –5.5dBV@VA=2.8V and less after dividing resistors externally.
When LIN bit is “1”, LINE input is selected. Then IPGA table of ALC1 is changed to LINE side.
LINE input
27kΩ
LIN/RIN
ALC1
22kΩ
typ.184kΩ
Figure 18. Example of LINEIN at VA=2.8V
MS0028-E-00
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2000/05