AMIS-722402 Datasheet, PDF (3/15 Pages) AMI SEMICONDUCTOR – Contact Image Sensor

AMIS-722402: Contact Image Sensor
Data Sheet
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 registers
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.
Unlike a CCD array, all of the 2400dpi, 1200dpi, 600dpi, and 300dpi arrays can operate with the same clock frequency.
Table 1: Select Resolution Conditions
Resolution
Select Resolution 1 (SR1)
2400dpi
L
1200dpi
L
600dpi
H
300dpi
H
Select Resolution 2 (SR2)
L
H
L
H
4.0 Functional Description
4.1 Input / Output Terminals
The AMIS-722402 image sensor has 13 pads that become inter-connected when they are cascaded end-to-end on a PCB and
packaged in an image sensing module. Their symbols and functions are listed in Table 2.
Table 2: Input and Output Terminals
Signal
I/O
Description
SI
I
Start pulse: Input to start a line scan (see discussion of the sensors unique features for further details)
Global start pulse:
GBST
I
Globally initializes the start inputs of all sensors and starts the scanning process of the first sensor (see discussion of the
sensors unique features for further details)
CLK
I
Clock: Clock input for the shift register
SIC
I
Start input control:
Input to control the Start Pulse to the first sensor (see discussion of the sensors unique features for further details)
Waveform select:
WS
I
Selects between two different readout modes, the waveform select input is left unconnected or held high for normal sampling
and held low for CDS sampling
VOUT
O
Video output voltage: Output video signal from the chip
VREF
I/O
Reference voltage: Reference input voltage for the amplifier output; sets the output’s reset (dark) level
VSS
I
Ground
VDD
I
Power supply
Internal bias voltage.
VBIAS
O
This is an internal bias voltage which should be connected via an external decoupling capacitor to Vdd on the modules’ PCB
for noise reduction. Special care may be required to minimize electro-magnetic interference coupling to this line.
Select resolution 1:
SR1
I
Selects the 2400, 1200, 600, or 300dpi modes in conjunction with SR2 (see discussion of the sensors unique features for
further details)
Select resolution 2:
SR2
I
Selects the 2400, 1200, 600, or 300dpi modes in conjunction with SR1 (see discussion of the sensors unique features for
further details)
SO
O
End of scan pulse: Output from the shift register at the end of a scan
AMI Semiconductor – Jan. 06, M-20499-004
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