NOIS1SM0250A-HHC ON Semiconductor, NOIS1SM0250A-HHC Datasheet - Page 11

• Manufacturer Part Number: NOIS1SM0250A-HHC
• Manufacturer: ON Semiconductor

Specifications of NOIS1SM0250A-HHC

• Lead Free Status / Rohs Status: Supplier Unconfirmed

Programmable Gain Amplifier
The signal from the column amplifiers is fed to an output amplifier
with four presettable gains (adjustable with pins G0 and G1). The
offset correction of this amplifier is done through a black
reference procedure. The signal from the output amplifier is
externally available on the analog output terminator of the
device.
Analog-to-Digital Converter
The on-chip 10-bit ADC is electrically separated from the other
circuits of the device. The ADC conversion range is set by the
voltages on VLOW_ADC (pin 47) and VHIGH_ADC (pin 70).
Make voltages on these pins equal to about 2 V on VLOW_ADC
and 4 V on VHIGH_ADC. The voltages are set by connecting
VLOW with 1.2 kto GND and VHIGH_ADC with 560 to V
This way, a resistor ladder is created as shown in
Figure 10. ADC Resistor Ladder
The internal ADC resistance varies according to temperature.
The resistance value increases approximately 4.4 /°C with
increasing temperature. If the ADC range is set externally with
resistors, the conversion range may vary with temperature. This
effect is cancelled out by not making use of resistors but directly
applying voltages on VLOW_ADC and VHIGH_ADC.
Pin 70: VHIGH_ADC
Pin 47: VLOW_ADC
R
R
R
ADC_VHIGH
ADC
ADC_VLOW
External
External
Internal
Rev. 7 | www.onsemi.com | Page 11 of 22
Figure
10.
DD
.
Timing and Readout of Image Sensor
Image Readout Procedure
A preamble or initialization phase is irrelevant. The sensor is
read out continuously. The first frame is generally saturated and
useless because there is no preceding reset of each pixel.
Image Readout
In an infinite uninterrupted loop, follow these steps for every line:
For all other lines do not pulse one of these SYNC_Y signals.
Readout Timing
The actual line readout process starts with addressing the line to
read. This is done either by initializing the YL pointer with a new
value or by shifting it one position beyond its previous value.
(Addressing the line has reset, YR is done in an analogous
fashion). During the "blanking time", after the new line is
addressed on the sensor, the built-in column-parallel double
sampling amplifiers are operated. This renders offset-corrected
values of the line under readout.
After the blanking time, the pixels of the row addressed by YL are
read by multiplexing all the pixels one by one to the serial output
chain. The pixel is selected by the X pointer and that pointer is
either initialized with a new value or an increment of the previous
position.
The time between row resets and their corresponding row
readouts is the effective exposure time (or integration time). This
time is proportional to the number of lines (DelayLines) between
the line currently under reset and the line currently under
readout: DelayLines = (YR - YL+1). This time is also equal to the
delay between the SYNC_YR pulse and the subsequent
SYNC_YR.
The effective integration time tint is calculated as delaylines x line
time. The line time is a function of four terms: the time to output
the desired number of pixels in the line (Wframe) and the
overhead ("blanking") time needed to select a new line and
perform the double sampling and reset operations.
1. Synchronize the read (YL) and/or reset (YR) registers:
2. Operate the double sampling column amplifiers with two
3. Perform a line readout:
❐
❐
❐
❐
❐
❐
RESETs. Apply one to reset the line that is currently selected
to produce the reset reference level for the double sampling
column amplifiers. Apply the other reset to another line
depending on the required integration time reduction.
SYNC_YL - to reinitiate the readout sequence to row position
Y1
SYNC_YR - to reinitiate the reset pointer to row position Y1
Reset the X read address shift register to the value in its
shadow register (X1).
Perform a pixel readout operation, operating the track/hold
and the ADC.
Shift the X read address shift register one position further.
Shift the Y read and reset address shift registers one position
further. If either of Y read or reset address shift register comes
to the end of the pixel array (or the ROI), wrap it around to
the start position by pulsing SYNC_YL.
NOIS1SM0250A