ak4683 AKM Semiconductor, Inc., ak4683 Datasheet - Page 44

• Manufacturer Part Number: ak4683
• Description: Asynchronous Multi-channel Audio Codec With Dir/t
• Manufacturer: AKM Semiconductor, Inc.

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Power supply voltage for the Headphone-Amp is supplied from the HVDD pin and centered on the HVDD/2 voltage.
When the MUTEN bit is “0”, the common voltage of Headphone-Amp falls and the outputs (HPL and HPR pins) go to
“L” (HVSS). When the MUTEN bit is “1”, the common voltage rises to HVDD/2. A capacitor between the MUTET pin
and ground reduces click noise at power-up. Rise/Fall time constant is proportional to HVDD voltage and the capacitor
at MUTET pin.
[Example]: A capacitor between the MUTET pin and ground = 1.0μF, HVDD=5V:
When PWHP bit is “0”, the Headphone-Amp is powered-down, and the outputs (HPL and HPR pins) go to “L”
(HVSS).
(1) Headphone-Amp power-up (PWHP bit = “1”). The outputs are still HVSS.
(2) Headphone-Amp common voltage rises up (MUTEN bit = “1”). Common voltage of Headphone-Amp is rising.
(3) Start the audio output after finishing the setup pf common voltage to prevent the clipping.
(4) Headphone-Amp common voltage falls down (MUTEN bit = “0”). Common voltage of Headphone-Amp is falling.
(5) Headphone-Amp power-down (PWHP bit = “0”). The outputs are HVSS. If the power supply is switched off or
The cut-off frequency (fc) of Headphone-Amp depends on the external resistor and capacitor. Table 41 shows the cut
off frequency and the output power for various resistor/capacitor combinations. The headphone impedance R
Output powers are shown at HVDD = 5V.
MS0427-E-02
Headphone Output
Headphone-Amp is powered-down before the common voltage goes to HVSS, some CLICK noise occurs.
Rise/fall time constant: τ = 120ms(typ)
PWHP bit
MUTEN bit
HPL pin,
HPR pin
R [Ω]
6.8
16
0
Figure 25. Power-up/Power-down Timing for Headphone-Amp
C [μF]
220
100
100
100
47
47
(1) (2)
Figure 26. External Circuit Example of Headphone
HP-AMP
AK4683
Table 41. External Circuit Example
fc [Hz]
100
149
106
(3)
45
70
50
R
- 44 -
(４)
C
Output Power [mW]@0dBFS
Headphone
(５)
16Ω
12.5
50
25
[AK4683]
L
2007/04
is 16Ω.