ak4648 AKM Semiconductor, Inc., ak4648 Datasheet - Page 14

• Manufacturer Part Number: ak4648
• Description: Stereo Codec With Mic/hp/spk-amp
• Manufacturer: AKM Semiconductor, Inc.

Parameter
Headphone-Amp Characteristics in Pseudo Cap-less mode:
Headphone Volume (HPG3-0 bits)
Output Voltage (Note 22)
S/(N+D)
S/N (A-weighted)
Interchannel Isolation
Interchannel Gain Mismatch
Load Resistance (Note 25)
Load Capacitance
Note 22. Output voltage is proportional to AVDD voltage.
Note 23. HPG = 0dB, HVDD=3.6V, R
Note 24. HPG = +3dB, HVDD=4.5V, R
Note 25. Load resistance is inserted between HPL pin (HPR pin) and HVCM pin.
MS0625-E-01
DAC → HPL/HPR pins, ALC=OFF, IVOL=0dB, DVOL=0dB; VBAT bit = “0”; PMHPC bit = “1”; unless otherwise
specified.
Volume Range
Gain Step: +3dB to –33dB
HPG = 0dB, 0dBFS, HVDD=3.6V, R
HPG = +3dB, 0dBFS, HVDD=4.5V, R
HPG = +3dB, -2dBFS, HVDD=3.6V, R
HPG = +3dB, 0dBFS, HVDD=4.5V, R
HPG = 0dB, −3dBFS, HVDD=3.6V, R
HPG = +3dB, −3dBFS, HVDD=4.5V, R
HPG = +3dB, -2dBFS, HVDD=3.6V, R
HPG = +3dB, 0dBFS, HVDD=4.5V, R
Vout = 0.6 x AVDD(typ.) @ HPG = 0dB, 0.848 x AVDD(typ.) @ HPG = +3dB
Note: Impedance between headphone and HVCM pin should be as lower as possible. If the impedance is
larger, crosstalk and distortion might be degraded.
Figure 3. Example external output circuit of HP-Amp in Pseudo Cap-less Mode
VCOM Amp for
HP-Amp
HP-Amp
L
L
L
=16Ω (Po=62.5mW)
=16Ω (Po=62.5mW)
L
L
=16Ω (Po=40mW)
=22.8Ω
=16Ω (Po=40mW)
L
L
C1 in Figure 3
C2 in Figure 3
=100Ω
=22.8Ω
(Note 23)
(Note 24)
(Note 23)
(Note 24)
(Note 23)
(Note 24)
L
L
=100Ω
=22.8Ω
L
=100Ω
HPL/HPR pin
HVCM pin
- 14 -
C1
0.22μF
10Ω
1.58
2.24
min
-33
1.5
30
80
40
16
-
-
-
-
-
-
-
-
-
-
-
6.8Ω
Measurement Point
C2
C2
1.98
typ
2.8
0.8
1.0
0.1
0.1
50
60
45
40
90
90
50
60
3
-
-
-
-
16Ω
max
2.38
3.36
300
4.5
0.8
0.8
+3
30
-
-
-
-
-
-
-
-
-
-
-
[AK4648]
2007/06
dBFS
dBFS
dBFS
dBFS
Units
Vrms
Vrms
Vpp
Vpp
dB
dB
dB
dB
dB
dB
dB
dB
pF
pF
Ω