First of all, thank you for your replies, as this is my first post in this Comunity.
I have an Analog Input to measure the output signal (in current) of a HV transducer. The transducer is suplied to +- 24V
The Analog Input consists on:
- TVS of Vbr=15V
- An array of resistors to become the current into voltage.
- A buffer with Op. Amp. OP4177 in Sallen Key configuation (1 stage). The supply of the Operational is bipolar and suplied to +- 12V
My problem is that, when a transient overvoltage hapens in HV section (this, in theory should not happen, but it does), the voltage in the AI goes avobe de 15V of the TVS; and after many transient overvoltages, the TVS goes into continious low impedance. This is fine, as it protects the OA, but I need to reduce the number of permanent failures of this stage.
So, my question here is:
Can I increase the Vbr level of the TVS to 24V without risk of breaking down the OA? If not, I need to add some alternative protection to reduce the permanent failure rates. Any Ideas?
I attach you the AI stage and de Absolut Maximum Ratings of the OP4177.
Thank you for your help.