AD9822 Analog Devices, AD9822 Datasheet - Page 11

• Manufacturer Part Number: AD9822
• Description: Complete 14-Bit CCD/CIS Signal Processor
• Manufacturer: Analog Devices

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 13 for a graph of the PGA
Gain versus PGA register code. The coding for the PGA registers is straight binary, with an all “zeros” word corresponding to the
minimum gain setting (1x) and an all “ones” word corresponding to the maximum gain setting (5.7x).
D8
Set to 0
0
0
0
0
*Power-on default value.
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 V shows the offset range as a function of the Bits D8 through D0.
D8
MSB
0
0
0
1
1
1
*Power-on default value.
REV. A
D7
0
0
1
0
0
1
D7
Set to 0
0
0
0
0
D6
0
0
1
0
0
1
D6
Set to 0
0
0
0
0
D5
0
0
1
0
0
1
D5
MSB
0
0
1
1
Table IV. PGA Gain Register Settings
Table V. Offset Register Settings
D4
0
0
1
0
0
1
D4
0
0
1
1
D3
0
0
1
1
•
•
•
–11–
D3
0
0
1
0
0
1
•
•
•
•
•
•
D2
0
0
1
1
D2
0
0
1
0
0
1
D1
0
0
1
1
D1
0
0
1
0
0
1
D0
LSB
0*
1
0
1
Gain (V/V)
1.0
1.013
5.4
5.7
•
•
•
D0
LSB
0*
1
1
0
1
1
AD9822
Offset (mV)
0
+1.2
+350
0
–1.2
–350
•
•
•
•
•
•
Gain (dB)
0.0
0.12
14.6
15.1
•
•
•