AD9822_15 Datasheet, PDF (14/20 Pages) Analog Devices – Complete 14-Bit CCD/CIS Signal Processor

AD9822
PGA Gain Registers
There are three PGA registers for individually programming the gain in the red, green, and blue channels. Bits D8, D7, and D6 in each
register must be set low, and Bits D5 through D0 control the gain range in 64 increments. See Figure 15 for the PGA gain vs. the PGA
register code. The coding for the PGA registers is straight binary, with an all 0s word corresponding to the minimum gain setting (1×)
and an all 1s word corresponding to the maximum gain setting (5.7×).
Table 9. PGA Gain Register Settings
D8
D7
D6
Set to 0
Set to 0
Set to 0
0
0
0
0
0
0
0
0
0
0
0
0
1 _{Power-on default value.}
D5
MSB
0
0
1
1
D4 D3 D2 D1 D0
LSB
0
0
0
0
0¹
0
0
0
0
1
•
•
•
1
1
1
1
0
1
1
1
1
1
Gain (V/V)
1.0
1.013
•
•
•
5.4
5.7
Gain (dB)
0.0
0.12
•
•
•
14.6
15.1
Offset Registers
There are three PGA registers for individually programming the offset in the red, green, and blue channels. Bits D8 through D0 control
the offset range from −350 mV to +350 mV in 512 increments. The coding for the offset registers is sign magnitude, with D8 as the sign
bit. Table 10 shows the offset range as a function of the Bits D8 through D0.
Table 10. Offset Register Settings
D8 (MSB) D7
D6
D5
D4
D3
D2
D1
D0 (LSB) Offset (mV)
0
0
0
0
0
0
0
0
0¹
0
0
0
0
0
0
0
0
0
1
+1.2
•
•
•
•
•
•
0
1
1
1
1
1
1
1
1
+350
1
0
0
0
0
0
0
0
0
0
1
0
0
0
0
0
0
0
1
−1.2
•
•
•
•
•
•
1
1
1
1
1
1
1
1
1
−350
1 _{Power-on default value.}
Rev. B | Page 14 of 20