AD9805JS Analog Devices Inc, AD9805JS Datasheet - Page 20

• Manufacturer Part Number: AD9805JS
• Description: IC CCD SIGNAL PROC 10BIT 64-PQFP
• Manufacturer: Analog Devices Inc
• Type: CCD Signal Processor, 12-Bitr

Specifications of AD9805JS

• Rohs Status: RoHS non-compliant
• Input Type: Logic
• Output Type: Logic
• Interface: Microprocessor
• Current - Supply: 86mA
• Mounting Type: Surface Mount
• Package / Case: 64-MQFP, 64-PQFP
• Operating Temperature (min): 0C
• Operating Temperature (max): 70C
• Operating Temperature Classification: Commercial
• Mounting: Surface Mount
• Pin Count: 64
• Lead Free Status / RoHS Status: Not Compliant

AD9807/AD9805
THE SECOND PIXEL IS GREEN, ALTERNATING BGBG...
WRITE A "1" TO THE LSB OF THE BAYER REGISTER
THE SECOND PIXEL IS RED, ALTERNATING GRGR...
CHANGE THE PGA AND INPUT OFFSET OF BLUE
BRING STRTLN LOW AT THE END OF THE LINE
BRING STRTLN LOW AT THE END OF THE LINE
SET PGA AND INPUT OFFSET FOR GREEN
PIXELS USING THE GREEN REGISTERS
APPLY AT LEAST ONE ADCCLK CYCLE
SET PGA AND INPUT OFFSET FOR RED
PIXELS USING THE BLUE REGISTERS
Figure 21. Bayer Mode Operation
REGISTERS FOR BLUE PIXELS
YES
THE FIRST PIXEL IS GREEN
THE FIRST PIXEL IS BLUE
BRING STRTLN LOW
BRING STRTLN HIGH
BRING STRTLN HIGH
(NEW FRAME)
GRGR AGAIN
NEXT LINE
?
NO
CHANGE GAIN
AND OFFSET
FOR RED PIXELS
WITH BLUE
REGISTERS
–20–
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.
10µF
0.1µF
0.1µF
0.1µF
+
0.1µF
+5
0.1µF
0.1µF
0.1µF
+5
+
10µF
10
12
14
15
1
2
3
4
5
6
7
8
AVDD
AVSS
CAPT
CAPT
CAPB
CAPB
REF
CML
AVSS
AVSS
AVSS
AVDD
Figure 22.
(PINS OMITTED FOR CLARITY)
AD9807/AD9805
DVSS
DVSS DVDD
28
52
DVSS
0.1µF
0.1µF
DVDD
+5
+5
29
51
DRVDD
DRVSS
41
40
REV. 0
0.1µF
+5