I was looking for a current sense amplifier with a high common mode voltage and I saw your circuit from the lab CN0218 which showed how you can achieve more than 500V of common mode voltage with the AD8212. In my design I have a source that is ~850V common and i think that this circuit would still work but i need to change the transistor Q1. I have looked through several different suppliers of transistors and i cannot seem to find a PNP transistor with more than -600V Vbe. Can you let me know two things:
1. Can you recommend a PNP device that can handle up to 850V common mode voltage? I have been unsuccessful in finding one.
2. Can i use two PNP devices at -500V in series instead? The picture below illustrates what i would like to see if possible if there isn't a feasible transistor from 1. (i took an snapshot from CN0218)
Thanks for your support!