CYII5SC1300AB-QWC Cypress Semiconductor Corp, CYII5SC1300AB-QWC Datasheet - Page 14

• Manufacturer Part Number: CYII5SC1300AB-QWC
• Manufacturer: Cypress Semiconductor Corp

Specifications of CYII5SC1300AB-QWC

• Lead Free Status / RoHS Status: Not Compliant

Non-linear and Linear Conversion Mode—’gamma’ Correction
Figure 15
(exponential) ADC conversion is intended for gamma-correction
of the images. It increases contrast in dark areas and reduces
contrast in bright areas. The non-linear transfer function is given
by:
Sensor Digital Outputs
The digital outputs of the IBIS5-B-1300 sensor are not designed
to drive large loads. Hence, the outputs cannot be used to
directly drive cables or long traces on the PCB. If it is required to
drive traces more than 5 inches long, it is advisable to use a
buffer for all the digital signals given out by the sensor.
Sensor Clock Inputs
The ADC_CLOCK and the SYS_CLOCK of the sensor are
typically 180 phase shifted from each other. However, depending
on the board layout, it is possible that there may be a variation
(increased phase shift of ADC_CLOCK with respect to
SYS_CLOCK) in the phase shift between the clocks.
So, it is recommended that the phase shift between the clocks is
maintained programmable.
Clock Jitter Requirements:
Min low time: 11.00ns
Min high time 11.00ns
max rise time 5ns
max fall time 5ns
Max Duty cycle: 47%-53%
Max period jitter: 150ps
It is important that the clock is stable, reproducible and has low
jitter.
clocks, both clock interact in the readout path and influence the
sensor performance.
Document #: 38-05710 Rev. *G
SYS_CLOCK and ADC_CLOCK are the most critical
shows the ADC transfer characteristic. The non-linear
Figure 15. Linear and Non-Linear ADC Conversion Characterisitics
With:
a = 5
b = 0.027
x = digital output code
Black Calibration
Due to slight variations in the chip fab process, the output analog
voltage of the PGA is not perfectly matched to the input analog
range of the ADC. As a result, users may observe a reduced
dynamic range when comparing sensors/cameras from different
lots. This is especially true in the dark as it is possible that a part
of the analog range gets clipped when it reaches the ADC.
For this reason, black calibration step is required.
Since this is a fixed setting, and varies very slightly with temper-
ature, the setting can be done at the factory itself.
While grabbing normal images, the settings can be loaded from
an on-board memory.
In the IBIS5 image sensor, black calibration step also tries to
match the output of the odd and even channels.
The steps for black calibration are -
1. Put the sensor in dark.
2. Change DAC_RAW such that no pixel or least number of
pixels (assuming there are defect pixels) have a zero ADC output
value.
3. Change DAC_FINE such that the average of the odd columns
is almost same as the even columns.
4. Change DAC_RAW again such that all pixels have a non-zero
output, but are as close to zero as possible.
5. Repeat for different gains.
Vin
=
ADC_VHIGH
+
(
ADC_VHIGH ADC_VLOW
–
CYII5SM1300AB
) *
---------------------------------------------- -
a*1023
a*x
Page 14 of 34
+
+
b*x
b*1023
2
2