AK4372 Datasheet, PDF (30/62 Pages) Asahi Kasei Microsystems – DAC with built-in PLL & HP-AMP

[AK4372]
< External Circuit of Headphone-Amp >
The cut-off frequency of the headphone-amp output depends on the external resistor and capacitor used. Table 23 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 AVDD = 2.4, 3.0 and 3.3V. The output voltage of the headphone-amp is 0.48 x AVDD
(Vpp) @−3dBFS.
HP-AMP
AK4372
R
C _Headphone
16Ω
Figure 23. External Circuit Example of Headphone
R [Ω]
0
6.8
16
C [μF]
fc [Hz]
fc [Hz]
BOOST=OFF BOOST=MIN
2.4V
Output Power [mW]
3.0V
3.3V
220
45
100
100
17
21
33
40
43
100
70
47
149
28
10
16
20
78
100
50
19
5
8
10
47
106
47
Table 23. Relationship of external circuit, output power and frequency response
< Wired OR with External Headphone-Amp >
When PMVCM=PMHPL=PMHPR bits = “0” and HPZ bit = “1”, Headphone-amp is powered-down and HPL/R pins are
pulled-down to VSS1 by 200kΩ (typ). In this setting, it is able to connect headphone-amp of AK4372 and external single
supply headphone-amp by “wired OR”.
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 24. HP-Amp Mode Setting (x: Don’t care)
HPL/R pins
VSS1
Pull-down by 200kΩ
VSS1
Normal Operation
(default)
AK4372
HPL pin
HPR pin
Headphone
Another
HP-Amp
Figure 24. Wired OR with External HP-Amp
MS0684-E-02
- 30 -
2008/12