INA322 Amplifier Circuit is humidity sensitive.

Jerry Shore

The circuit in this post: ( e2e.ti.com/.../349189) is very sensitive to humidity.

R2 and R1 are 0402 size parts. Any ideas?

Reducing the values but keeping the gain the same improves thing but the output still drops significantly with humidity.

Thanks!

over 9 years ago

0 Pete%20Semig over 9 years ago

TI__Mastermind 25815 points

Hello Jerry,

Have you sprayed or dipped the PCB in a conformal coating?

0 Jerry Shore over 9 years ago in reply to Pete%20Semig

Prodigy 120 points

No -- we really try to avoid coatings.

0 Pete%20Semig over 9 years ago in reply to Jerry Shore

TI__Mastermind 25815 points

Hello Jerry,

The only other suggestion I have is to ask the folks in our High Reliability forum. Therefore I have moved the post.

0 Pete%20Semig over 9 years ago in reply to Pete%20Semig

TI__Mastermind 25815 points

Hello Jerry,

After talking to a High Reliability engineer, he stated that they only work with high temp and space applications. So, I will move this back to the Precision Amplifiers forum. Sorry for the bounce. Unfortunately, though, outside of conformal coating I don't have any further suggestions.