LMT84: LMT84LP sensor failing after time

Kristopher Neild

Part Number: LMT84

I am using the LMT84LP temp sensor and I am running into issues where the output voltage will randomly drop from 0.9V to something in the range of 0.2 - 0.6V. It will jump around from a good output voltage to a bad output voltage far a while until the sensor fails with a very low output voltage. The sensor is powered from 3.3V and the filter is 100Ω in series with a 2.2uF cap to ground. The signal then goes into an STM32 processor.

I have a number of sensors connected like this but it is only 1 particular sensor that fails. Has anybody seen anything similar to this?

4 months ago

0 Ren Schackmann 4 months ago

TI__Mastermind 39675 points

Hi Kristopher,

Have you observed this on more than one assembly? Where is the failing sensor located? It sounds like EOS damage to that sensor.

thanks,

ren

0 Kristopher Neild 4 months ago in reply to Ren Schackmann

Prodigy 10 points

I have now seen this in 4 instruments so 4 separate assemblies. What is odd is that the bad sensor appears to work properly after being removed from the PCB and the replacement sensor that is soldered into the PCB also works fine.

0 Ren Schackmann 4 months ago in reply to Kristopher Neild

TI__Mastermind 39675 points

Since you show all channels having the same circuitry, I would assume that the problematic location is experiencing ESD or other EOS that the other locations are not. A broken device might still produce correct output under certain conditions.

Is there perhaps anything else different about the channels that you're not showing?

thanks,

ren

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LMT84: LMT84LP sensor failing after time