TMP235: low temperature power up problem

Hello Igor,

Are all parts behaving the same way at low temperature? Can you please confirm the layout and schematic for the device as well!

EDIT:

1. Does the behavior go away if the part is heated to room temp, i.e. the latch up condition is no longer seen even if the part is not power-cycled

2. What is the test setup for cooling the part. Is it freeze spray or a thermal chamber?

Hello Igor

Thanks for the information. The pause you mentioned is between the power supply going to 0V and then ramping up. Is that correct?

1. Does the behavior go away if the part is heated to room temp, i.e. the latch up condition is no longer seen even if the part is not power-cycled
2. What is the test setup for cooling the part. Is it freeze spray or a thermal chamber?
3. If you can change the power up ramp to be faster then does the issue occur?

Based on your previous post the answer for #2 seems to be a thermal chamber. Is that correct?

Hello Igor,

Thanks for the information, it helps. I would suggest increasing the decoupling cap to slow down the ramp up of the supply voltage. I don't have any parts that show the same behavior as of now, to test how large the cap needs to be. Also let me check if we can start a return process to understand why the part is failing as seen in your setup.

about 100us power supply rise time solves the problem

Hello Igor,

I hope the TMP235 device is working as expected since the change in the ramp time. Just to make sure we complete due diligence on the issue, can you please let us know the date code on the top of the package so that we can see if we can reproduce the issue on our side and ensure ongoing quality improvements?

The date code should be on the top of the package and a picture of the same should suffice.

Hello Igor,

Thanks for the information. When you mentioned earlier that you sped up the ramp rate from 0 to 3.3V in 100us, did you change the R=100 ohms and C=1uF?

Hello Igor,

It means that the earlier power supply had a very low current drive, that caused such a long time for the device to come up? If you can provide the details on the power supply and the load for the TMP235, I can try reproducing the issue with your schematic information at low temperature on few parts that I have.

If you cannot share it on the forum, please send me via the PM. I have sent you a friend request so that we can connect.