AD9925BBCZ Analog Devices Inc, AD9925BBCZ Datasheet - Page 38

• Manufacturer Part Number: AD9925BBCZ
• Description: IC CCD SIGNAL PROCESSOR 96CSPBGA
• Manufacturer: Analog Devices Inc
• Type: CCD Signal Processor, 12-Bitr

Specifications of AD9925BBCZ

• Input Type: Logic
• Output Type: Logic
• Interface: 3-Wire Serial
• Mounting Type: Surface Mount
• Package / Case: 96-CSPBGA
• Analog Front End Type: CCD
• Analog Front End Category: Video
• Interface Type: Serial (3-Wire)
• Sample Rate: 36MSPS
• Input Voltage Range: 0.8V
• Operating Supply Voltage (min): 2.7V
• Operating Supply Voltage (typ): 3V
• Operating Supply Voltage (max): 3.6V
• Resolution: 12b
• Number Of Adc's: 1
• Power Supply Type: Analog/Digital
• Operating Temp Range: -25C to 85C
• Operating Temperature Classification: Commercial
• Mounting: Surface Mount
• Pin Count: 96
• Package Type: CSPBGA
• Number Of Channels: 1
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Current - Supply: -
• Lead Free Status / RoHS Status: Compliant, Lead free / RoHS Compliant

AD9925
SUBCK Suppression
Normally, the S
the sensor gate lin VSG).
needs to be supp
line. The SUBCKSUPPRES
o
Readout after Exposure
After the exposure, the readout of the CCD data occurs, begin-
ning with the sensor gate (VSG) operation. By default, the
AD9925 is generating the VSG pulses in every field. In the case
where only a single exposure and a single readout frame is
needed, such as the CCD’s preview mode, the VSG and SUBCK
pulses can operate in every field.
However, in many cases, during readout, the SUBCK output
needs to be further suppressed until the readout is completed.
The READOUT register specifies the number of additional
fields after the exposure to continue the suppression of SUBCK.
READOUT can be programmed for zero to seven additional
fields and should be preprogrammed at startup, not at the same
time as the exposure write. A typical interlaced CCD frame
readout mode will generally require two additional fields of
SUBCK suppression (READOUT = 2). A 3-field, 6-phase CCD
will require three additional fields of SUBCK suppression after
the readout begins (READOUT = 3).
If the SUBCK output is required to start back up during the last
field of readout, simply program the READOUT register to one
less than the total number of CCD readout fields.
Like the exposure operation, the readout operation must be
triggered using the TRIGGER register.
Using the TRIGGER Register
As described above, by default, the AD9925 will output the
SUBCK and VSG signals on every field. This works well for
continuous single-field exposure and readout operations, such
as the CCD’s live preview mode. However, if the CCD requires a
longer exposure time, or if multiple readout fields are needed,
the TRIGGER register needs to initiate specific exposure and
readout sequences.
Typically, the exposure and readout bits in the TRIGGER regis-
ter are used together. This will initiate a complete exposure-plus
readout operation. Once the exposure has been completed, the
readout will automatically occur. The values in the EXPOSURE
and READOUT registers will determine the length of each
operation.
f the SUBCK pulses for lines following the VSG line.
UBC
ress
e (
Ks wil
ed for
l be
one
Wi
S re
gin to pulse on the line fol
th some CCDs, the SUBCK pu e
gister allows for the suppression
or more lines following th
lowin
e VSG
Rev. A | Page 38 of 96
ls
g
It is possible to independently trigger the readout operation
without triggering the exposure operation. This w
readout to occur at th
suppressed according to the value of the READOU
The TRIGGER regist
MSHUT, and VSUB signal transitions. Each of these signals is
individually controlled, although they will be dependent on the
triggering of the exposure and readout operation.
See Figure 49 for a complete example of triggering the exposure
and readout operations.
VSUB Control
The CCD readout bias (VSUB) can be programmed to accom-
modate different CCDs. Figure 48 shows two different modes
that are available. In Mode 0, VSUB goes active during the field
of the last SUBCK when the exposure begins. The on position
(rising edge in Figure 48) is programmable to any line within
the field. VSUB will remain active until the end of the image
readout. In Mode 1, the VSUB is not activated until the start of
the readout.
An additional function called VSUB keep-on is also available.
When this bit is set high, the VSUB output will remain on (active)
even after the readout has finished. To disable the VSUB, set
this bit back to low.
MSHUT and STROBE Control
MSHUT and STROBE operation is shown in Figure 49, Figure
50, and Figure 51. Table 20 shows the registers parameters for
controlling the MSHUT and STROBE outputs. The MSHUT
output is switched on with the MSHUTON registers, and it will
remain on until the location specified in the MSHUTOFF is
reached. The location of MSHUTOFF is fully programmable to
anywhere within the exposure period, using the FD (field), LN
(line), and PX (pixel) registers. The STROBE pulse is defined by
the on and off positions. STROBON_FD is the field in which
the STROBE is turned on, measured from the field containing
the last SUBCK before exposure begins. The STROBON_ LN
PX register gives the line and pixel positions with respect to
STROBON_FD. The STROBE off position is programmable to
any field, line, and pixel location with respect to the field of the
last SUBCK.
er is also used to control the STROBE,
e next VD, and the SUBCK output will be
ill cause the
T register.