PYTHON25K Datasheet, PDF (34/87 Pages) ON Semiconductor – PYTHON 25K/16K/12K/10K Global Shutter CMOS Image Sensors

NOIP1SN025KA, NOIP1SN016KA, NOIP1SN012KA, NOIP1SN010KA
Sensor Status
The currently used exposure and gain parameters are
reported by the sensor in registers 240 to 248. These status
registers are updated at the start of the frame in which these
parameters become active.
Temperature Diode
The temperature diode allows the monitoring of the sensor
die temperature during operation. The diode can be
connected through the pins td_anode and td_cathode.
The die temperature (Tdie), as a function of the measured
forward threshold voltage of the diode, with a known bias
current (Vdiode at bias 40 mA), is determined according to
the following formula:
T_die = (0.77–Vdiode at bias 40 mA)/0.00158°C
Temperature Sensor
The PYTHON has an on−chip temperature sensor which
returns a digital code (Tsensor) of the silicon junction
temperature. The Tsensor output is a 8−bit digital count
between 0 and 255, proportional to the temperature of the
silicon substrate. This reading can be translated directly to
a temperature reading in °C by calibrating the 8−bit readout
at 0°C and 85°C to achieve an output accuracy of ±2°C. The
Tsensor output can also be calibrated using a single
temperature point (example: room temperature or the
ambient temperature of the application), to achieve an
output accuracy of ±5°C.
Note that any process variation will result in an offset in
the bit count and that offset will remain within ±5°C over the
temperature range of 0°C and 85°C. Tsensor output digital
code can be read out through the SPI interface.
Output of the temperature sensor to the SPI:
tempd_reg_temp<7:0>: This is the 8−bit N count readout
proportional to temperature.
Input from the SPI:
The reg_tempd_enable is a global enable and this enables
or disables the temperature sensor when logic high or logic
low respectively. The temperature sensor is reset or disabled
when the input reg_tempd_enable is set to a digital low state.
Calibration using one temperature point
The temperature sensor resolution is fixed for a given type
of package for the operating range of 0°C to +85°C and
hence devices can be calibrated at any ambient temperature
of the application, with the device configured in the mode of
operation.
Interpreting the actual temperature for the digital code
readout:
The formula used is
T_J = R (Nread − Ncalib) + Tcalib
T_J = junction die temperature
R = resolution in degrees/LSB (typical 0.75 deg/LSB)
Nread = Tsensor output (LSB count between 0 and 255)
Tcalib = Tsensor calibration temperature
Ncalib = Tsensor output reading at Tcalib
Monitor Pins
The sensor features three logic monitor output pins. These
pins can provide internal state and synchronization
information to the outside system. These status pins can be
used during system setup or for system frame
synchronization.
The pins are named monitor0, monitor1, and monitor2.
The information provided on these pins is configured with
the register monitor_select (register 192[13:11]).
NOTE: Monitor indications are generated in the
sequencer. These signals lead the image and
synchronization data on the LVDS channels.
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