Other Parts Discussed in Thread: OPA2333-HT, OPA2333
Hi all,
Our team is working on a circuit involving the OPA2333P that is to be deployed in a very high temperature ambient environment. The circuit itself isn't very complex, it's a wheatstone bridge feeding into a diff amp.
As part of our testing, we have pushed this circuit to roughly155/160degC and it has failed, which is somewhat expected since we're pushing the OPA2333P beyond it's absolute max ratings in the datasheet. For various reasons, we expected the circuit to survive at 150degC and a little beyond and to prove it, we decided to do another experiment.
We configured the 2 opamps (in the one IC package) into simple voltage followers, each with their own biases, fed off the same power supply (circuit shown below). We tested this circuit at approximately 155degC for a few hours and the opamp has not failed. As a bit more info, all circuits were built on Veroboards with the actual Opamp IC soldered on to a small FR4 breakout board (due to it's tiny package).
Figure 1: voltage follower circuit (100nF caps are on the opamp power rails, just not shown in the circuit)
Is anyone able to shed light on this behaviour? What actually fails (on a semiconductor level) at this high temperature, and why is it failing in one instance and not in the other?
Cheers,
Umair
