AD9995KCP Analog Devices Inc, AD9995KCP Datasheet - Page 27

• Manufacturer Part Number: AD9995KCP
• Description: IC CCD SIGNAL PROCESSOR 56-LFCSP
• Manufacturer: Analog Devices Inc
• Type: CCD Signal Processor, 12-Bitr

Specifications of AD9995KCP

• Rohs Status: RoHS non-compliant
• Input Type: Logic
• Output Type: Logic
• Interface: 3-Wire Serial
• Current - Supply: 30mA
• Mounting Type: Surface Mount
• Package / Case: 56-LFCSP
• Analog Front End Type: CCD
• Analog Front End Category: Video
• Interface Type: Serial (3-Wire)
• Input Voltage Range: 0.5V
• 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: -20C to 85C
• Operating Temperature Classification: Commercial
• Mounting: Surface Mount
• Pin Count: 56
• Package Type: LFCSP EP
• Number Of Channels: 1
• Lead Free Status / RoHS Status: Not Compliant

If the exposure is generated using the TRIGGER register and the
EXPOSURE register is set to zero, the behavior of the SUBCK
will not be any different than the normal shutter or high precision
shutter operations, in which the TRIGGER register is not used.
SUBCK Suppression
Normally, the SUBCKs will begin to pulse on the line following
the sensor gate line (VSG). With some CCDs, the SUBCK pulse
needs to be suppressed for one or more lines following the VSG
line. The SUBCKSUPPRESS register allows for suppression of
the SUBCK pulses for additional lines following the VSG line.
Readout after Exposure
After the exposure, the readout of the CCD data occurs, beginning
with the sensor gate (VSG) operation. By default, the AD9995 is
generating the VSG pulses in every field. In the case where only a
single exposure and single readout frame are needed, such as the
CCD’s preview mode, the VSG and SUBCK pulses can be oper-
ating 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
Register
TRIGGER
READOUT
EXPOSURE
VDHDOFF
SUBCKPOL*
SUBCK1TOG*
SUBCK2TOG*
SUBCKNUM*
SUBCKSUPPRESS*
*Register is not VD updated, but is updated at the start of line after sensor gate line.
REV. 0
SUBCK
VSG
VD
NOTES
1. SUBCK MAY BE SUPPRESSED FOR MULTIPLE FIELDS BY PROGRAMMING THE EXPOSURE REGISTER GREATER THAN ZERO.
2. ABOVE EXAMPLE USES EXPOSURE = 1.
3. TRIGGER REGISTER MUST ALSO BE USED TO START THE LOW SPEED EXPOSURE.
4. VD/HD OUTPUTS MAY ALSO BE SUPPRESSED USING THE VDHDOFF REGISTER = 1.
EXPOSURE
TRIGGER
Length
5b
3b
12b
1b
1b
24b
24b
12b
12b
Figure 28. Low Speed Shutter Mode Using EXPOSURE Register
Range
On/Off for Five Signals
0–7 # of Fields
0–4095 # of Fields
On/Off
High/Low
0–4095 Pixel Locations
0–4095 Pixel Locations
1–4095 # of Pulses
0–4095 # of Pulses
Table XI. Shutter Mode Register Parameters
–27–
Description
Trigger for VSUB [0], MSHUT [1], STROBE [2], Exposure [3],
and Readout Start [4]
Number of Fields to Suppress SUBCK after Exposure
Number of Fields to Suppress to SUBCK and VSG during
Exposure Time (Low Speed Shutter)
Disable VD/HD Output during Exposure (1 = On, 0 = Off)
SUBCK Start Polarity for SUBCK1 and SUBCK2
Toggle Positions for First SUBCK Pulse (Normal Shutter)
Toggle Positions for Second SUBCK Pulse in Last Line
(High Precision)
Total Number of SUBCKs per Field at One Pulse per Line
Number of Lines to Further Suppress SUBCK after the VSG Line
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 sup-
pression 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 trig-
gered by using the TRIGGER register.
Using the TRIGGER Register
As described previously, by default the AD9995 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 is needed to initiate specific exposure and
readout sequences.
Typically, the exposure and readout bits in the TRIGGER
register 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 EXPO-
SURE and READOUT registers will determine the length of
each operation.
t
EXP
AD9995