Features
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Designed for Digital Photography, Graphic Arts, Medical and Scientific Applications
Pixel 14 µm x 14 µm Photomos with 100% Aperture
Image Zone: 28.67 mm x 28.67 mm
Frame Readout Through 1, 2 or 4 Outputs
Data Rates up to 4 x 20 MHz (Compatibility with 15 Frames/Second)
Possible Binning 2 x 2 Pixels (Format 1024 x 1024 with Pixels of 28 µm x 28 µm)
High Dynamic Range (up to 12600:1) even at:
– Room Temperature
– 20 MHz/Output
Very Low Dark Current (MPP Mode)
Optimized Resolution and Responsivity in the 400 - 1100 nm Spectrum
Other Possible Full Frame Operating Modes:
– 1536 x 2048 Pixels of 14 µm x 14 µm
– 768 x 1024 Pixels of 28 µm x 28 µm
Compatible with Fiber Optic Face Plate Coupling
On Request: Frame Transfer Architecture (On-chip Memory Defined by Mechanical
Shielding) Featuring:
– 1024 (V) x 2048 (H) Active Pixels of 14 µm x 14 µm
– 512 (V) x 1024 (H) Active Pixels of 28 µm x 28 µm
– 512 (V) x 2048 (H) Active Pixels of 14 µm x 14 µm
Full Field CCD
Image Sensor
2048 x 2048
Pixels
TH7899M
Figure 1.
TH7899M Organization
Rev. 2201A–IMAGE–02/02
1
General Description
The TH7899M sensor is a 2048 x 2048 full frame Charge Couple Device (CCD)
designed for a wide range of applications due to both its operating mode flexibility and
its high dynamic range combined with its high resolution. The device is 180° symmetri-
cal so if it is not plugged in the right side it will not be damaged.
The nominal photosensitive area is made up of 2048 x 2048 useful pixels split vertically
in 4 zones A, B, C and D. Each zone can be driven separately by four-phase clocks
(ΦP1
ΦP2 ΦP3
and
ΦP4)
allowing different operating modes as described in “Image
Area” on page 3.
There are two identical horizontal shift registers: one at the top of the image area (regis-
ter A) and one at the bottom (register B). At each end of the two readout registers, a
summing gate is located which can be clocked to allow a horizontal pixel summation in
front of the on-chip output amplifier.
Applications
The TH7899M sensor is particularly suited to the following applications:
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Digital photography
Medical applications
Graphic arts
Industrial applications
Scientific applications
Functional
Description
Pixel
The pixel size is 14 µm x 14 µm with 100% aperture. The following figures show the
pixel structure.
Figure 2.
Front View of a Photoelement
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TH7899M
2201A–IMAGE–02/02
TH7899M
Figure 3.
Cross Sectional View (AA') of a Photoelement and Potential Profile During
Integration
Image Area
The image area consists of an array of 2048 x 2048 useful photoelements for imaging.
The matrix also includes:
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7 columns of dark reference and 5 isolation columns (half covered) on the right and
left sides. The isolation columns are to ensure the 2048 active columns and are
100% photosensitive,
8 supplementary lines in each zone A B C and D; these lines are useful when using
an optical shield in case of frame transfer architecture with memory zone to correct
smearing (digital correction).
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Among these 8 lines in zones A and D, 3 lines at the top and at the bottom of the full
image area are masked with aluminium, all the other supplementary lines are
photosensitive.
The image area is divided into 4 parts of 520 lines each (electrically but not optically).
These 4 parts can be driven independently allowing different operating modes as
described hereunder.
Full Field Modes (No
Mechanical Shield On
Package)
In such cases a mechanical shutter is needed to shield the array from incident illumina-
tion during the readout period to avoid parasitic signal (smearing) particularly at low data
rates. Such a shutter is not necessary if no light is coming onto the photosensitive area
during the readout time (e.g. in case of pulsed light source).
There are mainly three different modes which can square with different optical formats,
with readout optimized in speed or with simplified operating conditions.
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Active Pixel
Number
2048 (V) x 2048 (H)
2048 (V) x 2048 (H)
1024 (V) x 2048 (H)
1536 (V) x 2048 (H)
1365 (V) x 2048 (H)
Image Zone Dimension
28.67 mm (V) x 28.67 mm (H)
28.67 mm (V) x 28.67 mm (H)
14.34 mm (V) x 28.67 mm (H)
21.50 mm (V) x 28.67 mm (H)
19.11 mm (V) x 28.67 mm (H)
Useful
Zones
A, B, C
and D
A, B, C
and D
C and D
B, C
and D
Used
Readout
Register
B
A and B
B
B
Number of
Possible
Outputs
1 or 2
2 or 4
1 or 2
1 or 2
Configu-
ration to
be Used
1
2
2
3
Characteristics
Simplified operating
conditions
2048 x 2048 optimized data
rate
Adapted optical format
Adapted optical format
Equivalent 24 x 36mm ratio
512 (V) x 2048 (H)
7.17 mm (V) x 28.67 mm (H)
A
A
1 or 2
3
Adapted optical format
Note:
1. Binned modes (2 x 2 or 2 x 1) can be used which will lead to specific binned formats in particular the format 1024 x 1024 with
an equivalent pixel size of 28 µm x 28 µm.
Frame Transfer Modes
(Option On Package On
Request)
These cases involve placing an optical shield in the package (on request) to define one
or two memory zones according to the application shown in the figures below.
Active Pixel
Number
1024 (V) x 2048 (H)
1024 (V) x 2048 (H)
Image Zone Dimension
14.34 mm (V) x 28.67 mm (H)
14.34 mm (H) x 28.67 mm (H)
Useful
Zones
C and D
B and C
Used
Readout
Register
B
A and B
Number of
Possible
Outputs
1 or 2
2 or 4
Configu-
ration to
be Used
4
5
Characteristics
1024 x 2048 simplified
operating conditions
1024 x 2048 optimized data
rate
512 (V) x 2048 (H)
7.17 mm (V) x 28.67 mm (H)
A
A
1 or 2
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Adapted optical format
Note:
1. Binned modes (2 x 2 or 2 x 1) can be used, this will lead to specific binned formats, in particular, the format 512 x 1024 with
an equivalent pixel size of 28 µm x 28 µm.
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TH7899M
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TH7899M
Horizontal Registers
The sensor has two readout registers located at the top (register A) and at the bottom
(register B) of the image area. They can be driven independently by two phase clocks.
Nevertheless to allow a multiple charge transfer direction for the useful pixels (left, right
or half left and half right), the two clocks are split into 6 clocks (ΦLA
i=1 to 6
for the A regis-
ter and
ΦLB
i=1 to 6
for the register B). The transfer direction is fixed by the connection
mode of the six clocks into 2 clocks.
The description of the connection with the transfer direction is described in “” on page 9.
The readout register has 2072 stages, with a further 18 extra stages at each end. What-
ever the chosen transfer direction for the useful pixels, the 18 extra pixels, the 7 dark
references and the 5 isolations are always transferred to the nearest output as shown in
the figure hereunder.
Figure 4.
A and B Readout Register Structure
The readout register can be driven in the MPP mode if necessary.
Binned Modes
Two types of summation can be performed:
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Vertical summation in each stage of the serial register (A or B)
Horizontal summation in an output summing well driven by
ΦS
clock and located at
each end of the readout registers (A and B).
Nevertheless, one summation can be performed in both the register and the output sum-
ming, allowing in this way, to have a resulting signal of (2 x 2) contiguous pixels from the
image area. Thus, the sensor is equivalent to a 1024 x 1024 array of a 28 µm x 28 µm
pixel. When using the binned mode with a charge level, after summation, smaller than
300 ke- (typical value) it is better (optimization of dynamic and linearity) to keep the con-
version factor at 7 µV/e- (with VGL = 1V and VDR = 13.5V). But for summing mode with
charge level, after binning, higher than 300 ke-, the conversion factor should be reduced
by increasing the VGL gate to 12V and the VDR reset drain to 15V. With such a method,
the saturation charge is optimized for the binning mode.
This summing technique leads to an increased signal to noise ratio, larger pixel size,
higher frame rates (for vertical binning only) but at the expense of a loss in resolution.
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2201A–IMAGE–02/02
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