AK4561 Datasheet, PDF (36/48 Pages) Asahi Kasei Microsystems – 16bit CODEC with built-in ALC and MIC/HP-Amp

ASAHI KASEI
AKM CONFIDENTIAL
[AK4561]
n Headphone Amplifiers
The output circuit of headphone amplifier does not need a capacitor to cancel DC because the headphone amplifier
includes center amplifier (HVCM). Load impedance of headphone amplifier is minimum 55Ω.
The output signals are muted when S8 bit is “0”, the headphone amplifiers become Power-Save-Mode. Then HPL/HPR
pin go Hi-z and HVCM pin is output to VCOM voltage. (Refer to Figure 23)
When PM5 bit is “0”, the headphone amplifiers can be powered-up completely. Then HPL/HPR pins become Hi-z and
HVCM pin becomes “L” (AGND). (Refer to Figure 24)
When PD pin changes from “L” to “H” after power-up, the output signals from headphone amplifier is muted, the
headphone amplifiers are powered-up by Power-Save-Mode. After that, S8 bit should be changed into “0” before
headphone amplifier is done by the normal operation.
S8
-
+
-
+
PM5
HPL/HPR
HVCM
Figure 22. Headphone-Amps Normal Operation
S8
-
+
-
+
PM5
HPL/HPR
HVCM
Figure 23. Headphone-Amps Power-Save-Mode
S8
-
+
-
+
PM5
HPL/HPR
HVCM
Figure 24. Headphone-Amps Power-Down-Mode
Rev. 0.9
- 36 -
2000/09