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Datasheet A2TPMI
CONTROL UNIT / SERIAL INTERFACE
The operation characteristics of the A2TPMI have to be configured with a set of internal random access
registers. All parameters / configurations are permanently stored in E2PROM in parallel, Configuration
is usually done during factory calibration and does not need any user input.
The control unit offers via serial interface access to all the registers, i.e. the internal parameters of the
A2TPMI. The serial interface is a two wire bi-directional synchronous (SDAT, SCLK) type. A2TPMI sen-
sors are in general factory calibrated and therefore there is no need to use the serial interface for stan-
dard applications.
The SDAT- / SCLK pins are internally pulled up to VDD and can be left unconnected. If the SDAT /
SCLK pins will be connected in the application, ensure signal conformity to the serial interface specifica-
tion. Subsequent undefined signals applied to these pins, may change the configuration and lead to
malfunctioning of the sensor.
For detailed information about the serial interface refer to application note: A2TPMI Serial Interface de-
scription, or contact PerkinElmer application support.
OUTPUT CONFIGURATION
The A2TPMI offers various output configurations, which can be configured via the serial communication
interface by means of integrated analog switches. For each output it can be individually selected
whether the output operates in ‘Analog mode’ or in ‘Comparator mode’.
In ‘Analog mode’ the output signal represents the measured IR radiation, respectively the temperature
as an analog DC voltage.
In ‘Comparator mode’ the measured IR radiation, respectively the temperature is compared to a pro-
grammed threshold. For slowly changing signals an additional hysteresis can be configured. If the
measured signal is above the threshold, +5VDC (logical high) is applied to the output. If the measured
signal is below the threshold, 0VDC (logical low)is applied to the output.
For detailed information about the output configuration refer to application note: A2TPMI Serial Interface
description, or contact PerkinElmer application support.
A2TPMI Datasheet Rev4
Page 10 of 21
Rev. Oct 2003
PERKINELMER [ PERKINELMER OPTOELECTRONICS ]
