AK4640_05 AKM [Asahi Kasei Microsystems], AK4640_05 Datasheet - Page 37

• Manufacturer Part Number: AK4640_05
• Description: 16-Bit ?? CODEC with MIC/HP/SPK-AMP
• Manufacturer: AKM [Asahi Kasei Microsystems]

ASAHI KASEI
The cut-off frequency of Headphone-amp output depends on the external resistor and capacitor used. Table 21 shows the
cut off frequency and the output power for various resistor/capacitor combinations. The headphone impedance R
Output powers are shown at HVDD = 2.7, 3.0 and 3.3V. The output voltage of headphone is 0.6 x AVDD (Vpp).
When an external resistor R is smaller than 12Ω, put an oscillation prevention circuit (0.22µF±20% capacitor and
10Ω±20% resistor) because it has the possibility that Headphone-amp oscillates.
MS0273-E-02
R [Ω]
6.2
6.2
16
16
C [µF]
100
100
47
47
Figure 26. External Circuit Example of Headphone
BOOST=OFF
HP-AMP
AK4640
fc [Hz]
152.5
105.8
71.2
49.7
Table 21. External Circuit Example
10Ω +/- 20%
0.22µ +/- 20%
BOOST=MID
R
- 37 -
fc [Hz]
63
43
27
20
C
Headphone
16Ω
2.7V
10.0
10.0
4.8
4.8
Output Power [mW]
3.0V
12.4
12.4
6.0
6.0
3.3V
15.0
15.0
7.2
7.2
[AK4640]
L
2005/04
is 16Ω.