I've been working on a LCR/Impedence meter and want to protect my inputs from possible damage if I forget to discharge a large cap.
I know I've seen various types of diodes and relays used for that purpose. But from what I've read and experienced, the larger diodes can cause degradation and relays would be a pain in the ass.
Then I remembered using a TVS array from TI(TPD2E2U06-Q1) to protect my usb signal lines on a prior project. With a minimum break down voltage of 6.5VDC and a stand off voltage of 5.5VDC, I thought it would be perfect. It has what looks like a 0Db insertion loss out past 100Mhz(I'll be using a max of 500Khz, and more likely 100Khz and below). The line capacitance is only 15pF, I'll have more than this in parasitics. This thing is mostly being built to deal with small impedances/resistances, miliohms and the like(I have a VNA that can handle larger stuff/higher testing signals) and a 5.5VDC cutoff will be plenty for this. I will also be putting two of them in parallel.
Now the question, did I interpret the data sheet correctly? Meaning will it protect my inputs(my front end AD630's are powered at +/- 12VDC, so they are safe until 13VDC) from a live cap and not greatly effect the measurements? If it comes down to it, I don't care if these things act like popcorn, at $.60, they are a LOT cheaper than my AD630s...
Here is another question, would adding a 2 or 5 watt resister in the TVS's ground leg help out here? If They