LUPA-1300 Datasheet, PDF (24/48 Pages) Cypress Semiconductor – 1.3 M Pixel High Speed CMOS Image Sensor

LUPA-1300
Datasheet
3.8.2 Biasing and analog signals
Besides the biasing signals, the only analog signals are the output signals Out1 –
Out16. Each output signal is analog with respect to the voltage level, but is discrete
in time. This means that on the speed of Clock_x, the outputs change to a different
level, depending on the illumination of the corresponding pixels.
The biasing signals determine the speed and power dissipation of the different
modules on chip. These biasing signals have to be connected trough a resistor to
ground or power supply and should be decoupled with a capacitor. If the sensor is
working properly, each of the biasing signals will have a dc-voltage depending on the
resistor value and on the internal circuitry. These dc-voltages can be used to check
the operation of the image sensor. Table 8 gives the different biasing signals, the way
they should be connected, and the expected dc-voltage. Due to small process
variations, these dc-voltages change from chip to chip and 10% variation is possible.
Signal
Comment
Pre_load
Col_load
Psf_load
Nsf_load
Load_out
Decx_load
Decy_load
Connect with 10KΩ to Vdda and capacitor of 100nF
to Gnd
Connect with 2MΩ to Vdda and capacitor of 100nF to
Gnd
Connect with 240KΩ to Gnd and capacitor of 100nF
to Vdda
Connect with 100KΩ to Vdda and capacitor of 100nF
to Gnd
Connect with 27KΩ to Voo and capacitor of 100nF to
Gnd
Connect with 27KΩ to Gnd and capacitor of 100nF to
Vdd
Connect with 27KΩ to Gnd and capacitor of 100nF to
Vdd
Table 8 : overview of biasing signals
Expected dc-
level
2.0V
0.9V
3.7V
1.3V
1.6V
2.8V
2.8V
Each resistor controls the speed and power dissipation of the corresponding module,
as this resistor determines the current required to charge and/or discharge internal
nodes inside the module.
A decoupling with a small capacitor is advisable to reduce the HF noise onto the
analog signals. Only the capacitor on the Pre_load signal can be omitted.
3.8.3 Pixel array signals
Figure 4 in paragraph 2.2 is a schematic representation of the pixel as used in the
LUPA design. The applied signals to this pixel are: reset, sample, Precharge,
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Contact [e-mail] Document # : 38-05711 Rev.**( Revision 3.1) Page 24 of 48