AK4642EN Datasheet, PDF (48/83 Pages) Asahi Kasei Microsystems – Stereo CODEC with MIC/HP/SPK-AMP

ASAHI KASEI
[AK4642EN]
When BOOST=OFF, the cut-off frequency (fc) of Headphone-Amp depends on the external resistor and capacitor. This
fc can be shifted to lower frequency by using bass boost function. Table 39 shows the cut off frequency and the output
power for various resistor/capacitor combinations. The headphone impedance R_L is 16Ω. Output powers are shown at
HVDD = 2.7, 3.0 and 3.3V. The output voltage of headphone is 0.6 x AVDD (Vpp).
When an external resistor R is smaller than 12Ω, put an oscillation prevention circuit (0.22µF±20% capacitor and
10Ω±20% resistor) because it has the possibility that Headphone-Amp oscillates.
HP-AMP
AK4642
R
0.22µ
10Ω
C _Headphone
16Ω
HPG bit R [Ω]
6.8
0
16
0
1
100
Figure 32. External Circuit Example of Headphone
C [µF]
100
47
100
47
220
100
22
10
fc [Hz]
fc [Hz]
BOOST=OFF BOOST=MIN
@fs=44.1kHz
70
28
149
78
50
19
106
47
45
17
100
43
62
25
137
69
Table 39. External Circuit Example
Output Power [mW]@0dBFS
2.7V
3.0V
3.3V
10.1
12.5
15.1
5.1
6.3
7.7
33
41
50
0.9
1.1
1.3
MS0420-E-00
- 48 -
2005/09