AK4953A Datasheet, PDF (55/96 Pages) Asahi Kasei Microsystems – 24bit Stereo CODEC with MIC/HP/SPK-AMP

[AK4953A]
■ Headphone Amplifier (HPL/HPR pins)
The positive voltage of the headphone amplifier uses the power supply to the DVDD pin, therefore 150mA of the
maximum power supply capacity is needed. The internal charge pump circuit generates negative voltage (PVEE) from
AVDD voltage. The headphone amplifier output is single-ended and centered around on VSS (0V). Therefore, the
capacitor for AC-coupling can be removed. The minimum load resistance is 16Ω. When HPM bit = “1”, the DAC output
signal is output to HPL and HPR pins as (L+R)/2 mono signal.
<External Circuit of Headphone-Amp>
An oscillation prevention circuit (0.22μF±20% capacitor and 100Ω±20% resistor) should be put because it has the
possibility that Headphone-Amp oscillates in type of headphone.
DAC
HP-AMP
AK4953A
Headphone
0.22μ
16Ω
100Ω
Figure 38. External Circuit of Headphone
When HPZ bit = “0” and PMHPL, PMHPR bits = “1”, headphone outputs are in normal operation.
When PMHPL and PMHPR bits = “0”, the headphone-amps are powered-down completely. At that time, the HPL and
HPR pins go to VSS voltage via the internal pulled-down resistor. The pulled-down resistor is 10Ω (typ). The HPL and
HPR pins become Hi-Z state by setting HPZ bit to “1” when PMHPL and PMHPR bit = “0”.
The power-up time of the headphone-amps is 35ms (max.), and power-down is executed immediately.
PMVCM
bit
x
x
1
1
PMHPL/R
bits
HPZ bit
Mode
HPL/R pins
0
0
Power-down & Mute
Pull-down by 10Ω (typ)
0
1
Power-down
Hi-Z
1
0
Normal Operation
Normal Operation
1
1
N/A
N/A
Table 53. Headphone Output Status (x: Don’t’ care, N/A: Not available)
(default)
MS1252-E-00
- 55 -
2010/10