ACS-1024-LG Photon Vision Systems, Inc., ACS-1024-LG Datasheet - Page 25

• Manufacturer Part Number: ACS-1024-LG
• Description: Image Sensor, CMOS|CCD, 1026x1026 Pixels, 132pin LCC
• Manufacturer: Photon Vision Systems, Inc.

CHARACTERIZATION CRITERIA
Pixel Read Rate
Read rate is the frequency at which adjacent pixels can be read. Specification requires maximum operation at 5.0 MHz as a limit. Testing pixel rate at 5.0
MHz. Therefore, CLK_IN_2X will be at 10.0 MHz at 50% duty cycle.
Full Well
Full well (or Saturation Exposure) is the maximum number of photon and/or dark current generated electrons a pixel can hold. Full well is based on the
capacitance of the pixel at a given bias. Full well is made by measuring the capacitance of all pixels for the operational bias.
Quantum Efficiency
Quantum Efficiency is a measurement of the pixel ability to capture photon generated charge at a given wavelength. This is measured at 25nm increments over
the 300 to 1100 nm range. Measurements are taken using a stable light source that is filtered using a monochromator. The exiting light from the
monochromator is collimated to provide a uniform flux that overfills a portion of the sensor area. The flux at a given wavelength is measured using a calibrated
radiometer and then the device under test is substituted.
Linearity
Linearity is an equal corresponding output signal of the sensor for a given amount of photon incident on the pixel active area. Linearity is measured numerous
ways. The most straight forward method is plotting the saturation exposure measurement from 5% to 70% of full well and applying a “best fit” straight line
plot and finding the greatest deviation (error) in terms of percent of full well.
Dark Signal
Dark signal is the accumulated electrons for a given integration period, that were not photon generated. There are a few sources in CMOS circuits for the dark
current and the dark current levels will vary even for a given process. Dark current will be measured at 1.0 sec. integration time at 25 degrees C.
Read Noise
Read noise is the temporal or time variant noise in the analog signal. Read noise does not include Fixed Pattern Noise (FPN) or dark current. FPN and dark
current are fixed levels per pixel for a given temperature, illumination and pixel. Read noise will be measured at the output of the imager with proper loading
and Bandwidth limitations. A high gain probe will be used twice. One measurement will be to measure the background noise of the test setup. The second
will be to measure the video noise using the test setup. The noise of the imager will be calculated by dividing out the gain back to 1X and subtracting the test
setup noise from the measured signal. Since noise sources add in quadrature, the test setup noise will be subtracted accordingly.
Image lag
Image lag is the amount of residual signal in terms of percent of full well on the current frame of video after injecting the previous frame of video. Image lag
will be measured by illuminating a number of pixels (TBD) to 50% of saturation for one frame and then rereading those pixels for the next and subsequent
frames without light exposure. Any remaining residual signal will be measured and recorded in terms of percent of full well.
Dynamic Range
Dynamic range is normally calculated by taking the full well value and dividing by the Root Mean Squared (rms.) of the temporal read noise. In terms of dB it
is twenty times the log of the calculated value.
100%
70%
Product DATASHEET ACS PDS0003 Subject to change without notice. Page 25 of 26
Maximum deviation from Ideal is
percent linearity error
Photon Vision Systems, Inc.
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