AD9807JS View Datasheet(PDF) - Analog Devices
Part Name
Description
Manufacturer
AD9807JS Datasheet PDF : 24 Pages
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AD9807/AD9805
SET PGA AND INPUT OFFSET FOR GREEN
PIXELS USING THE GREEN REGISTERS
SET PGA AND INPUT OFFSET FOR RED
PIXELS USING THE BLUE REGISTERS
BRING STRTLN LOW
WRITE A "1" TO THE LSB OF THE BAYER REGISTER
APPLY AT LEAST ONE ADCCLK CYCLE
BRING STRTLN HIGH
THE FIRST PIXEL IS GREEN
THE SECOND PIXEL IS RED, ALTERNATING GRGR...
CHANGE GAIN
AND OFFSET
FOR RED PIXELS
WITH BLUE
REGISTERS
BRING STRTLN LOW AT THE END OF THE LINE
YES
NEXT LINE
GRGR AGAIN
(NEW FRAME)
?
NO
CHANGE THE PGA AND INPUT OFFSET OF BLUE
REGISTERS FOR BLUE PIXELS
BRING STRTLN HIGH
THE FIRST PIXEL IS BLUE
THE SECOND PIXEL IS GREEN, ALTERNATING BGBG...
BRING STRTLN LOW AT THE END OF THE LINE
Figure 21. Bayer Mode Operation
Grounding and Decoupling
Figure 22 shows the recommended decoupling capacitors and
ground connections for the AD9807/AD9805. Notice that all of
the power and ground connections are common for the analog
and digital portions of the chip. This would be the best way to
connect the device on a board containing a large number of
digital components. By treating the AD9807/AD9805 as an
analog component, the on-board digital circuitry is considered
“quiet digital” and the digital supply pins are connected to the
clean analog supply and analog ground plane. For this tech-
nique to work well, it is important that the digital supply pins be
well decoupled to the analog ground plane and that the digital
outputs of the AD9807/AD9805 are buffered to minimize the
digital drive current. The buffers would be referred to the digital
supply and ground. This scheme is preferable to tying the digital
portion of the AD9807/AD9805 to a noisy digital ground and
power plane, capacitively coupling noise to the analog circuitry
within the device. The AD9807/AD9805 evaluation boards use
this grounding method, shown in Figures 26 and 27. If a
minimum amount of digital circuitry exists on the board, it is
possible that the power and ground connections of the AD9807
can be separated; be sure to maintain a single point connection
between the two ground planes at the AD9807/AD9805.
+5
0.1µF
0.1µF
1
AVDD
2
AVSS
3
CAPT
0.1µF
+
4 CAPT
10µF 5
CAPB
0.1µF
6 CAPB
7 REF
+
10µF
0.1µF
0.1µF
8
CML
10 AVSS
12 AVSS
0.1µF
14 AVSS
15 AVDD
+5
+5
0.1µF
52
51
DVSS
AD9807/AD9805
(PINS OMITTED FOR CLARITY)
41
DRVDD
DRVSS 40
DDVVSSSS DVDDVDD
28
29
0.1µF
+5
+5
0.1µF
Figure 22.
–20–
REV. 0
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