AK4645 Datasheet, PDF (63/96 Pages) Asahi Kasei Microsystems – Stereo CODEC with MIC/HP-AMP

ASAHI KASEI
HP-AMP
AK4645
CR
0.22µ
10Ω
Headphone
16Ω
[AK4645]
Figure 57. External Circuit Example of Headphone
HPG bit R [Ω]
0
0
6.8
16
0
1
100
C [µF]
220
100
100
47
100
47
220
100
22
10
fc [Hz]
fc [Hz]
Output Power [mW]@0dBFS
BOOST
=OFF
BOOST
=MIN
@fs=44.1kHz
HVDD=3.0V
AVDD=3.0V
HVDD=3.3V
AVDD=3.3V
HVDD=5V
AVDD=3.3V
45
17
25.3
30.6
30.6
100
43
70
28
12.5
15.1
15.1
149
78
50
19
106
47
6.3
7.7
7.7
45
100
17
43
51
(Note 41)
62
(Note 41)
70
62
25
137
69
1.1
1.3
1.3
Table 55. External Circuit Example
Note 40. Output power at 16Ω load.
Note 41. Output signal is clipped.
<Headphone-Amp PSRR>
When HVDD is directly supplied from the battery in the mobile phone system, RF noise may influences headphone
output performance. When VBAT bit is set to “1”, HP-Amp PSRR for the noise applied to HVDD is improved. In this
case, HP-Amp common voltage is 0.64 x AVDD (typ). When AVDD is 3.3V, common voltage is 2.1V. Therefore, when
HVDD voltage becomes lower than 4.2V, the output signal will be clipped easily.
VBAT bit
0
Common Voltage [V]
0.5 x HVDD
Table 56. HP-Amp Common Voltage
1
0.64 x AVDD
<Wired OR with External Headphone-Amp>
When PMVCM=PMHPL=PMHPR bits = “0” and HPZ bit = “1”, HP-Amp is powered-down and HPL/R pins are
pulled-down to HVSS by 200kΩ (typ). In this setting, it is available to connect HP-Amp of AK4645 and external single
supply HP-Amp by “wired OR”. In this mode, power supply current is 20µA(typ).
PMVCM
x
0
1
1
PMHPL/R
0
0
1
1
HPMTN
HPZ
Mode
x
0
Power-down & Mute
x
1
Power-down
0
x
Mute
1
x
Normal Operation
Table 57. HP-Amp Mode Setting (x: Don’t care)
HPL/R pins
HVSS
Pull-down by 200kΩ
HVSS
Normal Operation
Default
MS0543-E-00
- 63 -
2006/09