AK4648 Datasheet, PDF (74/119 Pages) Asahi Kasei Microsystems – Stereo CODEC with MIC/HP/SPK-AMP

[AK4648]
<Connection with mono headphone>
The AK4648 can be connected with mono headphone by using Headphone-Amp power management bit and HPZ bit. As
right channel of mono headphone is usually connected to GND, the right channel of Headphone-Amp must be Hi-Z. Here
are the power up sequence in Single-ended Mode and Pseudo Cap-less Mode.
1. Single-ended Mode
(1) Power-down Headphone-amp: PMHPL=PMHPR=HPZ bits = “0”
HPL/HPR pins output VSS2.
(2) Power-up left channel of Headphone-amp: PMHPL = “1”
Left channel of Headphone-amp is powered-up and HPL pin outputs VSS2.
(3) Change pull-down resistor of right channel of Headphone-amp: HPZ bit = “1”
HPR pin is pulled-down by 200kΩ(typ.) to VSS2.
(4) Release mute of Headphone-amp: HPMTN bit: “0” Æ 1
HPL pin outputs the signal and HPR pin is pulled-down by 200kΩ (typ.) to VSS2.
2. Pseudo Cap-less Mode
(1) Power-down of Headphone-amp: PMHPL=PMHPR=PMHPC=HPZ bits = “0”
HPL/HPR/HVCM pins output VSS2.
(2) Power-up left channel and common buffer of Headphone-amp: PMHPL = PMHPC bits = “1”
Left channel and common buffer of Headphone-amp are powered-up and they output VSS2.
(3) Change pull-down resistor of right channel of Headphone-amp: HPZ bit = “1”
HPR pin is pulled-down by 200kΩ(typ.) to VSS2.
(4) Release mute of Headhone-amp: HPMTN bit: “0” Æ 1
HPL pin outputs the signal. HPR pin is pulled-down by 200kΩ (typ.) to VSS2 and outputs HVCM voltage.
MS0625-E-01
- 74 -
2007/06