TMP01 Temperature Out-of-Range Warning

This is a TMP01 temperature out-of-range warning circuit. This circuit is used to generate a temperature out-of-range warning signal. This circuit is usually used in sensitive equipment calibrated to work over a limited temperature range. This circuit can be done by connecting the two open-collector outputs of the TMP01 together into a wired-OR configuration. Here is the schematic diagram of the circuit:

To give a temperature range of 10°C around room temperature (25°C), R3, R1, and R2 are used. When the temperature in the equipment falls below 15°C, The output signal is not-OVER and when the temperature rises above 35°C, the output signal is not-UNDER. Then, the LED will turn ON. The LED can be subtituted with any of the switching devices or a simple pull-up resistor to give a logic output for controlling the instrument. [Circuit’s schematic diagram source:]