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ADT6401 Output Problem

Thread Summary

The user is experiencing incorrect operation of ADT6401 temperature switches on their board, which shut down the board at room temperature. The issue is due to the part not entering the correct mode when the Vcc rise time is greater than 10ms, causing floating inputs to be misinterpreted as GND. The user tested the ADT6401 and found that it checks its inputs 2.5ms after power-up, leading to incorrect latching of input states with slow Vcc rise times. A potential alternative is the ADT6501, which has factory-set trip points in a similar package.
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Hi,

We are using two ADT6401 temperature switches on our board. They are open-drain output. We use one for the high temperature (+85 degrees celcius) and one for the low temperature (-45 degrees celcius). Our schematic is attached.


Temperature switches can shutdown our board. While we are testing the board at room temperature, our board shuts down because one of the temperature switches pulls their output low. We could not understand which of them. But the temperature is very far away from both high and low limits. So temperature switches do not operate correctly, that's for sure.

Our low temp. switch inputs are Float - GND - Float. If the float on the S2 pin, is measured as GND some time, the temperature setting goes to +65 degrees celcius. Could this be a problem? Or could it be a soldering effect?

Thanks,


Celil

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