HAMAMATSU C7921CA Datasheet
IMAGE SENSOR
Flat panel sensor
C7921CA
High resolution and high frame rate
Flat panel sensor C7921CA is a digital X-ray image sensor newly developed as key devices for non-destructive inspection, biomedical imaging,
X-ray microscopy and other real-time X-ray imaging applications requiring high resolution and high image quality. C7921CA consists of a sensor
board and a control board, both assembled in a thin, flat and compact package. The sensor board contains a CsI scintillator plate, a twodimensional photodiode array with FET switches and a signal processing IC chip. The photodiode array has a 1056 × 1056 pixel format with
minimized blooming and is highly sensitive to bluish green light emitted from the CsI scintillator. Each row of pixels is addressed in sequence by
the vertical shift register connected to the gate line.
Light emission occurs when X-rays are absorbed in the CsI scintillator. This light emission enters directly into the two-dimensional photodiode
array where an electric charge is stored in each pixel according to the light intensity. This charge is then transferred to the corresponding data line
by applying a control signal to the vertical shift register.
The sensor board also has 8 charge sensitive amplifier arrays each having 132 channel amplifiers with a horizontal shift register. These amplifiers
with a total of 1056 channels are connected to a CDS (Correlated Double Sampling) circuit that senses the charge on each video line and sends it
as the analog video signal from each amplifier array. The control board converts the analog video signal into a 12-bit digital signal and outputs it to
an external frame grabber from a 12-bit parallel port.
C7921CA delivers a frame rate of 16 frames per second using 4 × 4 binning and is ideal for high frame rate applications, also ideal for
applications requiring high resolution because of its 50 µm pixel size. Massive digital image data can easily be monitored on a display unit by
using a frame grabber board and video memory installed in the PC. C7921CA will prove ideal tools for real-time X-ray imaging and processing
where easy-to-use, high-resolution X-ray digital image sensors are needed.
Applications
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Non-destructive inspection
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Digital X-ray photography
■ Block diagram
PIXEL NUMBER
12
SCINTILLATOR
(52.8 mm × 52.8 mm)
AMP ARRAY No. 1
10561055
211221111057
PHOTODIODE
ARRAY
11151361115135
AMP ARRAY No. 8
SHIFT REGISTER
IntExt
TIMING
PULSE
GENERATOR
BIAS
GENERATER
Features
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High quality image: 1056 × 1056 pixels
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Pixel size: 50 × 50 µm
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No image distortion
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Digital output (12 bits)
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High-speed imaging by binning operation:
16 frames/s (4 × 4 binning)
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Wide dynamic range
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High cost performance
EXTERNAL POWER SUPPLY
A. Vdd, D. Vdd V (±7.5)
(not attached)
IntExt
BINNING
(bin0, bin1)
OSCILLATOR
ExtTrg
Vsync
Hsync
Pclk
BUFFER
AMP
BUFFER
AMP
PROCESSING
AMP
PROCESSING
AMP
A/D
FIFO
A/D FIFO
VIDEO OUTPUT
(12 BIT DIGITAL)
KACCC0170EA
1
Flat panel sensor
Vsync+
(RS-422)
Hsync+
(RS-422)
Hsync+
(RS-422)
Pclk+
(RS-422)
Data1 - 12
(RS-422)
The number of n is 132
Tvc (1 FRAME)
Thd
Thdpw Thc (1 LINE)
Tvdpw
Thdpw Thc (1 LINE)
Tpd
Tpdb
Tpc (1 PIXEL)
Tppw
Tpdb
1 2 n-1 n n+1
8n-1
8n
TdcTdd
C7921CA
■ Functional specification
Parameter Specification
Readout Charge amplifier array
Feedback capacitance of each amplifier 0.15 pF
Video output (Data1 - 12) RS-422 (differential) 12 bit
Output data rate 6.25 MHz
Synchronous signal (Vsync, Hsync, Pclk) RS-422 (differential)
bin0, 1, ExtTrg, IntExt TTL
■ Absolute maximum ratings (Ta=25 °C)
Parameter Symbol Valu e Unit
Supply voltage for digital circuitry (+5 V) D.vdd +6.0 V
Supply voltage for analog circuitry (+5 V) A.vdd +6.0 V
Supply voltage for analog circuitry (±7.5 V) V(+/-7.5) ±12 V
Input voltage (bin0, 1, ExtTrg, IntExt) Vin 0 to 6.0 V
Operating temperature (not condensed) Topr 0 to +35 °C
Storage temperature (not condensed) Ts tg 0 to +50 °C
■ Specification (Unless otherwise noted, Typ. Ta=25 °C A.vdd= 5.0 V, D.vdd= 5.0 V, V (±7.5)= ±7.5 V)
Parameter Symbol Specification Unit
Pixel size - 50 µm
Active area - 52.8 × 52.8 mm
Pixel number - 1056 × 1056 pixels
Number of active pixels - 1032 × 1032 pixels
Frame speed (single operation) Sf (int) 4 frame/s
Frame speed (2 × 2 binning) - 8 frame/s
Frame speed (4 × 4 binning) - 16 frame/s
Frame speed external (single operation ) Sf (ext) Sf (int) to 0.1 frame/s
Noise (rms.) N (rms.) 1000 electrons
Saturation charge Csat 2.9 M electrons
Resolution Reso 8 line pairs/mm
Dynamic range - 2900 Defect line * - 10 Max. lines
Scintillator - CsI -
* Without a couple of adjacent defect line that has no response.
■ Timing chart
To acquire images through an image grabber board, parameters that match the following timing chart should be described in the
software program or parameter file.
Internal mode
KACCC0167EA
2
ExtTrg
(TTL)
Vsync+
(RS-422)
External mode
FROM Tvc TO 10 s
RECOMMENDATION: 50 % OF FRAME TIME
Tvc - TvdpwTvd
Flat panel sensor
C7921CA
1 × 1 mode (Typ.)
Pclk
Data1-12
2 × 2 mode (Typ.)
Hsync
Pclk
Data1-12
Hsync+, Pclk and Data 1-12 are the same as internal trigger mode.
KACCC0139EB
Parameter Symbol Value Unit
Delay time (only external trigger mode) Tvd 450 µs
Cycle time Tvc 243 msVsync
Dummy pulse width Tvdpw 920 µs
Delay time Thd 2.8 µs
Cycle time Thc 230 µsHsync
Dummy pulse width Thdpw 59 µs
Delay time Tpd 150 ns
Cycle time Tpc 160 ns
Pulse width Tppw 85 ns
Delay time between each block Tpdb 480 ns
Delay time Tdd 50 ns
Cycle time Tdc 160 ns
Parameter Symbol Value Unit
Delay time (only external trigger mode) Tvd 450 µs
Cycle time Tvc 122 msVsync
Dummy pulse width Tvdpw 920 µs
Delay time Thd 2.8 µs
Cycle time Thc 230 µs
Dummy pulse width Thdpw 140 µs
Delay time Tpd 150 ns
Cycle time Tpc 160 ns
Pulse width Tppw 85 ns
Delay time between each block Tpdb 480 ns
Delay time Tdd 50 ns
Cycle time Tdc 160 ns
4 × 4 mode (Typ.)
Parameter Symbol Value Unit
Delay time (only external trigger mode) Tvd 450 µs
Vsync
Pclk
Data1-12
Note) The numbers of siginificant figures is two. (except Tvc)
Cycle time Tvc 62 ms
Dummy pulse width Tvdpw 920 µs
Delay time Thd 2.8 µs
Cycle time Thc 230 µsHsync
Dummy pulse width Thdpw 190 µs
Delay time Tpd 150 ns
Cycle time Tpc 160 ns
Pulse width Tppw 85 ns
Delay time between each block Tpdb 480 ns
Delay time Tdd 50 ns
Cycle time Tdc 160 ns
3
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