AK4647VN AKM [Asahi Kasei Microsystems], AK4647VN Datasheet - Page 44

• Manufacturer Part Number: AK4647VN
• Description: Stereo CODEC with MIC/HP-AMP
• Manufacturer: AKM [Asahi Kasei Microsystems]

ASAHI KASEI
Power supply voltage for the Headphone-Amp is supplied from the HVDD pin and centered on the HVDD/2 voltage. The
load resistance and output voltage are specified by HVDD voltage. HPG bit selects the output voltage (see Table 39).
When the HPMTN bit is “0”, the common voltage of Headphone-Amp falls and the outputs (HPL and HPR pins) go to
“L” (HVSS). When the HPMTN bit is “1”, the common voltage rises to HVDD/2. A capacitor between the MUTET pin
and ground reduces pop noise at power-up. Rise/Fall time constant is in proportional to HVDD voltage and the capacitor
at MUTET pin.
[Example]: A capacitor between the MUTET pin and ground = 1.0μF, HVDD=3.3V:
When PMHPL and PMHPR bits are “0”, the Headphone-Amp is powered-down, and the outputs (HPL and HPR pins) go
to “L” (HVSS).
(1) Headphone-Amp power-up (PMHPL, PMHPR bit = “1”). The outputs are still HVSS.
(2) Headphone-Amp common voltage rises up (HPMTN bit = “1”). Common voltage of Headphone-Amp is rising.
(3) Headphone-Amp common voltage falls down (HPMTN bit = “0”). Common voltage of Headphone-Amp is falling.
(4) Headphone-Amp power-down (PMHPL, PMHPR bit = “0”). The outputs are HVSS. If the power supply is switched
MS0566-E-00
Headphone Output
off or Headphone-Amp is powered-down before the common voltage goes to HVSS, some POP noise occurs.
Rise/fall time constant:
Time until the common goes to HVSS when HPMTN bit = “1”
PMHPL bit,
PMHPR bit
HPMTN bit
HPL pin,
HPR pin
Load Resistance (min)
Output Voltage [Vpp]
HPG bit
HVDD
Table 39. Headphone-Amp Output Voltage and Load Resistance
Figure 33. Power-up/Power-down Timing for Headphone-Amp
(1) (2)
τ
= 100ms(typ), 250ms(max)
0.6 x AVDD
2.6 ∼ 5.25V
- 44 -
22Ω
(3)
0
(4)
“0”: 500ms(max)
0.91 x AVDD
4.0 ∼ 5.25V
100Ω
1
[AK4647]
2006/11