Other Parts Discussed in Thread: THS4551, THS4561, LMH5401
Following up on this thread, there are number of FDA datasheets that could use this correction,
This development did originally come from Jim Karki's article where he got this far (the active input Z), but could not reach the closed form quadratic for Rt that I eventually got and put into all of these datasheets. Somehow, I got to an erroneous result on the resulting Za looking into Rg1 that combines with Rt to give the matched input Z. This result does of course apply to all earlier FDA's (and ADI's as well of course) that were done prior to the closed form solutions I developed and started publishing in 2011 for the ISL55210 FDA.
https://www.ti.com/lit/an/slyt310/slyt310.pdf
The parts that need this update include (and there may be others)
The ones I was working on,
THS4541 Eq. 11
THS4551 Eq. 4
THS4561 Eq. 4
and then the Ft. Collins group doing the LMH5401 copied that material
LMH5401 Eq. 7
