I work on industrial UT instruments. When calibration them, a very expensive Rohde & Schwarz RF STEP attenuator can be used. I want to protect its attenuation pads from an external "pulser" input in case of an accident hooking it up to an instrument or board set. That pulser can be -300volts, 10ns Rise Time and anywhere from 30ns to 500ns in width.
For brief periods of time, the Agilent 33250A generator can survive the pulser, and the Siglents survive too, but modern attenuators seem to vaporize easily internally.
For certification I use HP355E and HP355F attenuators, with custom control and custom support software I wrote and they are very good. You can hit them with one of those "pulsers" and they "Thank you, give me more", not so much a R&S with a $5K repair bill when a pad vaporizes, if they will even support the older ones any more.
I am thinking back to back 6.2v Zener Diodes across the output and then to ground and then a very light fuse in series with the output in a pomoma box. I am not worried about what that does to the bandwidth. All calibrations (tweaking) are done at 5MHz, sinewave, 1vpp. Any loss or BW attenuation would most likely be relative. What I am thinking it that the ZENERS would not be fast enough to protect against the pulse.
What components could be used that react very fast for output protection?
Thanks
Dave