NOIS1SM0250A Datasheet, PDF (10/25 Pages) ON Semiconductor – Radiation Tolerant CMOS Image Sensor

Sync_YL
Clk_YL
Ld_Y
9
A8...A0
S
R
NOIS1SM0250A
SENSOR ARCHITECTURE
9
512
Pixel Array
512
512 by 512 Pixels
Col
Sel
9
Rst
512
Column Amplifiers
512
9
Rst
Progr. Gain
Sig ^Amplifier
X Address
Decoder / Shift Register
Clk_YR
SyncYR
10
D9...D0
Clk_ADC
Ain
Aout
Ld_X
Figure 7. STAR250 Schematic
The base line of the STAR250 sensor design consists of
an imager with a 512 by 512 array of active pixels at 25 mm
pitch. The detector contains on-chip correction for FPN in
the column amplifiers, a programmable gain output
amplifier, and a 10-bit ADC. Through additional preset
registers, the start position of a window can be programmed
to enable fast read out of only part of the detector array.
Pixel Structure
The image sensor consists of several building blocks as
outlined in Figure 7. The central element is a 512 by 512
pixel array with square pixels at 25 mm pitch. Unlike
classical designs, the pixels of this sensor contain four
photodiodes. This configuration enhances the MTF and
reduces the PRNU. Figure 8 shows an electrical diagram of
the pixel structure. The four photodiodes are connected in
parallel to the reset transistor (T1). Transistor T2 converts
the charge, collected on the photo diode node, to a voltage
signal that is connected to the column bus by T3. The reset
and read entrance of the pixel are connected to one of the Y
shift registers.
T1
Reset
Read
T2
T3
Figure 8. STAR250 Pixel Structure
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