ak4561 AKM Semiconductor, Inc., ak4561 Datasheet - Page 32

• Manufacturer Part Number: ak4561
• Description: 16bit Codec With Built-in Alc And Mic/hp-amp
• Manufacturer: AKM Semiconductor, Inc.

AKM CONFIDENTIAL
ASAHI KASEI
[AK4561]
n BEEP Input
When S9 bit is “1”, input signal from BEEP pin can be output from MOUT pin. Normally, BEEP pin is connected with
AC coupling.
Input impedance of BEEP pin is typically 50k and centered around VCOM voltage. Maximum input voltage to BEEP
pin is –5.5dBV.
n Analog Volume (OPGA)
The AK4561 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 16ms.
These periods are value at fs=32kHz (FS bit = “0”) or fs=48kHz (FS bit = “1”).
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.
In case of writing to the control register continually, the control register should be written by an interval more than zero
crossing timeout. If an appointed interval is written, there is possible to the different value the IPGA value of L/R
channels.
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 ) of OPGL/OPGR.
Power supply for analog volume enables when PM6 or PM5 bits is “1”.
The initial value is 0dB at exiting power-down.
LOUT2/ROUT2
Ca
typ.110k
OPGA
OPGL/OPGR
Figure 14. Connect LOUT2/ROUT2 with OPGL/OPGR
n LINE input
In case of LINE input, input impedance of LIN/RIN is 184k (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 S2 bit is “1”, LINE input is selected. Then IPGA table of ALC is changed to LINE side.
ALC
LIN/RIN
27k
Line Input
typ.184k
22k
Figure 15. Example of LINEIN at VA=2.8V
Rev. 0.9
2000/09
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