ak4644 AKM Semiconductor, Inc., ak4644 Datasheet - Page 48

• Manufacturer Part Number: ak4644
• Description: Stereo Codec With Mic/hp/rcv-amp
• Manufacturer: AKM Semiconductor, Inc.

ASAHI KASEI
The AK4644 includes the digital de-emphasis filter (tc = 50/15µs) by IIR filter. Setting the DEM1-0 bits enables the
de-emphasis filter (Table 37).
The BST1-0 bits control the amount of low frequency boost applied to the DAC output signal (Table 38). If the BST1-0
bits are set to “01” (MIN Level), use a 47µF capacitor for AC-coupling. If the boosted signal exceeds full scale, the analog
output clips to the full scale. Figure 38 shows the boost frequency response at –20dB signal input.
MS0477-E-01
De-emphasis Filter
Bass Boost Function
-10
-15
-20
-25
-5
0
10
MAX
MID
MIN
Figure 38. Bass Boost Frequency Response (fs=44.1kHz)
DEM1
BST1
0
0
1
1
0
0
1
1
Table 37. De-emphasis Control
Boost Filter (fs=44.1kHz)
100
Table 38. Bass Boost Control
DEM0
0
1
0
1
BST0
0
1
0
1
Frequency [Hz]
- 48 -
44.1kHz
48kHz
32kHz
Mode
OFF
Mode
MAX
MIN
MID
OFF
1000
Default
Default
10000
[AK4644]
2006/10