AA4002 Datasheet, PDF (14/22 Pages) BCD Semiconductor Manufacturing Limited – STEREO 2W AUDIO POWER AMPLIFIER

Data Sheet
STEREO 2W AUDIO POWER AMPLIFIER
AA4002
Application Information (Continued)
Table 1. Volume Attenuation vs. DC VOL Pin Voltage
f_BS = 1 2πR_BSC_BS ^{..............................................(4)}
Assuming R_BS=R_F=R_I=20kΩ, C_BS=0.068µF and
f_BS=117Hz, the bass boost characteristic is shown in
Figure 21.
Fixed Gain/Adjustable Gain Loop, MODE
pin, DC Volume Control
The AA4002 can be set in fixed gain or adjustable
gain, according to applying high or low level to MODE
pin (pin 4). Low level is for fixed gain, High level is
for adjustable gain, which permits to change volume by
applying various DC voltages to DC VOL pin (pin7).
Table 1 shows the relationship of Volume Attenuation
vs. the voltage of DC VOL pin.
There are 31 steps from 0 to -78dB; step size is
different for different volume control voltage,
1dB/step from 0dB to -6dB,
2dB/step from -6dB to -36dB,
3dB/step from -36dB to -47dB,
4dB/step from -47db to -51dB,
5dB/step from -51dB to -66dB,
The last step is 12dB from -66dB to -78dB.
Figure 23. Volume Attenuation vs. DC VOL Pin Voltage
For example, increasing voltage applied to DC VOL
pin from 3.437V (point B in Figure 23) to 3.562V
(point D), gain will change one step from -4dB to -3dB
(point F).
Sep. 2006 Rev. 1. 1
Attenuation (dB)
0
-1
-2
-3
-4
-5
-6
-8
-10
-12
-14
-16
-18
-20
-22
-24
-26
-28
-30
-32
-34
-36
-39
-42
-45
-47
-51
-56
-61
-66
-78
V_DD=5V
High Level (V)
5
3.937
3.812
3.687
3.562
3.437
3.312
3.187
3.06
2.937
2.812
2.687
2.562
2.437
2.312
2.187
2.062
1.937
1.812
1.687
1.562
1.437
1.312
1.187
1.062
0.937
0.812
0.687
0.562
0.437
0.312
Low Level (V)
3.875
3.750
3.625
3.500
3.375
3.250
3.125
3.000
2.875
2.750
2.625
2.500
2.375
2.250
2.125
2.000
1.875
1.750
1.625
1.500
1.375
1.250
1.125
1.000
0.875
0.750
0.625
0.500
0.375
0.250
0
BCD Semiconductor Manufacturing Limited
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