AK4343 Datasheet, PDF (37/98 Pages) Asahi Kasei Microsystems – Stereo DAC with HP/RCV/SPK-AMP

ASAHI KASEI
[AK4343]
„ Gain Amplifier
The AK4343 has a gain amplifier. The gain is selected by the MGAIN1-0 bits (see Table 22). The typical input impedance
is 60kΩ(typ)@MGAIN1-0 bits = “00” or 30kΩ(typ)@MGAIN1-0 bits = “01”, “10” or “11”.
MGAIN1 bit
0
0
1
1
MGAIN0 bit Input Gain
0
0dB
1
+20dB
0
+26dB
1
+32dB
Table 22. Input Gain
Default
„ Digital EQ/HPF/LPF
The AK4343 performs wind-noise reduction filter, stereo separation emphasis, gain compensation and ALC (Automatic
Level Control) by digital domain for input data (Figure 32). FIL1, FIL3 and EQ blocks are IIR filters of 1^st order. The
filter coefficient of FIL3, EQ and FIL1 blocks can be set to any value. Refer to the section of “ALC operation” about
ALC.
FIL3 coefficient also sets the attenuation of the stereo separation emphasis.
The combination of GN1-0 bit (Table 23) and EQ coefficient set the compensation gain.
FIL1 and FIL3 blocks become HPF when F1AS and F3AS bits are “0” and become LPF when F1AS and F3AS bits are
“1”, respectively.
When EQ and FIL1 bits are “0”, EQ and FIL1 blocks become “through” (0dB). When FIL3 bit is “0”, FIL3 block become
“MUTE”. When each filter coefficient is changed, each filter should be set to “through” (“MUTE” in case of FIL3).
Wind-noise reduction
FIL1
Stereo separation emphasis
FIL3
Gain compensation
EQ
Gain
ALC
An y coefficient
F1A13-0
F1B13-0
F1AS
An y coefficient 0dB _∼ -10dB
F3A13-0 MUTE
F3B13-0 (set by
F3AS
FIL3 coefficient)
An y coefficient
EQA15-0
EQB13-0
EQC15-0
+12dB ∼ 0dB
GN1-0
+24/+12/0dB
Figure 32. Digital EQ/HPF/LPF
GN1
GN0
Gain
0
0
0dB
Default
0
1
+12dB
1
x
+24dB
Table 23. Gain select of gain block (x: Don’t care)
MS0478-E-01
- 37 -
2006/10