AMIS-722402 Datasheet, PDF (7/15 Pages) AMI SEMICONDUCTOR – Contact Image Sensor

AMIS-722402: Contact Image Sensor
Data Sheet
5.1 Definitions of Electro-optical Specifications
All electrical specifications will be measured at a pixel rate of 3.0MHz, a temperature of 25^°C, Vdd = 3.3V, Vref = 0.35V and at an
integration time of 0.9ms for 300dpi, 1.8ms for 600dpi, 3.76ms for 1200dpi, and 7.2ms for 2400dpi. The average output voltage Vpavg,
which is defined as the voltage difference between the average pixel level in the light and the average pixel level in the dark, will be
adjusted to approximately 1.0V, unless stated otherwise. A linear array of uniform green LED’s will be used as the light source for
measurements requiring illumination, unless stated otherwise. As a guideline, the recommended load on the output should be
1KΩ<RL<10kΩ. All measurements will be taken with a 2kΩ load on the output.
1. Selectable resolutions.
The sensor allows for four selectable resolutions; 2400dpi, 1200dpi, 600dpi, and 300dpi, which are controlled by the SR1 and SR2 inputs. Table 1 details how
each resolution mode is selected. In the 2400dpi mode, all 1376 pixels are clocked out, whereas in the 1200dpi mode, Pixels 1 and 2 are combined, 3 and 4 are
combined and so on up to Pixels 1375 and 1376 being combined. One half of the pixel amplifiers and one half of the scanning register are then disabled. As a
result, sensitivity in the 1200dpi mode will be twice that of the 2400dpi mode and the 1200dpi readout time will be approximately half of the 2400dpi readout time.
Similarly, in the 600dpi mode, Pixels 1-4 are combined, Pixels 5-8 are combined and so on up to Pixels 1373-1376 being combined. Only one quarter of the pixel
amplifiers and shift registers are then used. The 600dpi sensitivity will be four times that of the 2400dpi, and the readout time will be one quarter of the 2400dpi
readout time. In the 300dpi mode, Pixels 1-8 are combined, Pixels 9-16 are combined and so on up to Pixels 1369-1376 being combined. Only one eighth of the
pixel amplifiers and shift registers are then used. The 300dpi sensitivity will be eight times that of the 2400dpi, and the readout time will be one eighth of the
2400dpi readout time.
2. Dark output voltage (Vd).
Vd is the average dark output level and is essentially the offset level of the video output in the dark. The dark level is set by the voltage on VREF and is
recommended to be set externally to a voltage of 0.35V for optimal module operation.
3. Dark output non-uniformity (Ud).
Ud = Vdmax-Vdmin, where Vdmax is the maximum pixel output voltage in the dark and Vdmin is the minimum pixel output voltage in the dark.
4. Photo-response non-uniformity (Up).
Up = ((Vpmax-Vpavg)/Vpavg) x 100% or ((Vpavg-Vpmin)/Vpavg) x 100%, whichever is the greater, where Vpmax is the maximum pixel output voltage in the light,
Vpmin is the minimum pixel output voltage in the light and Vpavg is average output voltage of all pixels in the light.
5. Adjacent photo-response non-uniformity (Upn).
Upn = Max ((Vpn, Vpn+1) / Min (Vpn, Vpn+1)) x 100%, where Vpn is the pixel output voltage of pixel n in the light.
6. Sensor-to-sensor photo-response non-uniformity (Usensor).
Usensor = (Vpavg - Wavg) / Wavg), where Wavg is the average output of all sensors on the same wafer that pass all other specifications.
7. Saturation voltage (VSat) is defined as the maximum video output voltage swing measured from the dark level to the saturation level. It is measured by using the
module LED light source with the module imaging a uniform white target. The LED light level is increased until the output voltage no longer increases with an
increase in the LED brightness. The dark level is set by the voltage on VREF and is recommended to be set externally to a voltage of 0.35V for optimal module
operation.
8. Sensitivity (Sv) is defined as the slope of the Vpavg vs. Exposure curve.
9. Photo-response linearity (PRL).
Photo-response linearity is defined as the max. deviation of response compared to a best fit line as a percentage of full scale, where full scale is the maximum
value of the linearity range of operation; approx 0.75V. Photo-response linearity is specified within the linearity range of operation, approx 0.1-0.75V.
10. Individual pixel noise in rms (P_noise).
The individual pixel noise in rms is defined as the standard deviation of each pixel in the dark. The maximum of all pixel standard deviations is the maximum
individual pixel noise in rms. This can also be thought of as output referred noise as it is measured at the sensor output.
11. Average pixel noise in rms (Pavg_noise).
The average pixel noise in rms is defined as the average of all pixel standard deviations in the dark. A 2.5mV rms value has a peak-peak equivalent of 15mV. This
can also be thought of as output referred noise as it is measured at the sensor output.
12. Row noise in rms (Row_noise)
Each chip is binned into four equal bins and the row noise in rms is defined as the standard deviation of each bin. The row noise specification does not include any
noise due to external sources.
AMI Semiconductor – Jan. 06, M-20499-004
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