AR0330 Datasheet, PDF (44/77 Pages) ON Semiconductor – CMOS Digital Image Sensor

AR0330: 1/3-Inch CMOS Digital Image Sensor
Gain Stages
Gain Stages
The analog gain stages of the AR0330 sensor are shown in Figure 30. The sensor analog
gain stage consists of column amplifiers and a variable ADC reference. The sensor will
apply the same analog gain to each color channel. Digital gain can be configured to
separate levels for each color channel.
Figure 30: Gain Stages in AR0330 Sensor
ADC
Reference
Digital Gain
with Dithering
Coarse Gain:
1x to 15.992x
1x, 2x, 4x, 8x (128 steps per 6dB)
Fine Gain:
“xxxx.Yyyy”
1-2x: 16 steps
xxxx(15-0)
2-4x: 8 steps yyyyyyy( 127/128 to 0)
4-8x: 4 steps
The level of analog gain applied is controlled by the coarse_gain and fine_gain registers.
The analog readout can be configured differently for each gain level. The recommended
gain tables are listed in Table 32. It is recommended that these registers are configured
before streaming images.
Table 32: Recommended Sensor Analog Gain Tables
COARSE_GAIN
R0x3060[
5:4]
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
Gain
(x)
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
FINE_GAIN
R0x3060
[3:0]
0
1
2
3
4
5
6
7
8
9
10
11
12
13
14
Gain
(x)
1.00
1.03
1.07
1.10
1.14
1.19
1.23
1.28
1.33
1.39
1.45
1.52
1.60
1.68
1.78
Total Gain
(x)
(dB)
1.00 0.00
1.03 0.26
1.07 0.56
1.10 0.86
1.14 1.16
1.19 1.46
1.23 1.80
1.28 2.14
1.33 2.50
1.39 2.87
1.45 3.25
1.52 3.66
1.60 4.08
1.68 4.53
1.78 5.00
COARSE_GAIN
R0x3060[
5:4]
0
1
1
1
1
1
1
1
1
2
2
2
2
3
Gain
(x)
1x
2x
2x
2x
2x
2x
2x
2x
2x
4x
4x
4x
4x
8x
FINE_GAIN
R0x3060
[3:0]
15
0
2
4
6
8
10
12
14
0
4
8
12
0
Gain
(x)
1.88
1.00
1.07
1.14
1.23
1.33
1.45
1.60
1.78
1.00
1.14
1.33
1.60
1.00
Total Gain
(x)
(dB)
1.88
5.49
2.00
6.00
2.13
6.58
2.29
7.18
2.46
7.82
2.67
8.52
2.91
9.28
3.20 10.10
3.56 11.02
4.00 12.00
4.57 13.20
5.33 14.54
6.40 16.12
8.00 18.00
AR0330_DS Rev. U Pub. 4/15 EN
44
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