I've simulated an adjustable gain instrumentation amplifier circuit using two AD8040 that appears to work very well. I'm curious if there is an instrumentation amp version that is functionally equivalent? Perhaps one based on the 8040? See pic…
For a RRIO replacement for the ADA4851-4, I would recommend the AD8040 The AD8040 is 125MHz RRIO low power quad op amp, that should meet your needs nicely.
High Speed Amplifiers
If he would go for a replacement part, I would suggest AD8040. It is a quad, rail-to-rail input and output high speed amplifier with an input voltage range of extending 200 mV beyond each supply rail having no phase reversal.
For its + 5 V…
I downloaded the ad4897 spice model to use in a simulattion of a 2nd order 3.6 MHz LPF.
I use LtSpice.
The model would not run until I commented out the BF value for the npn model. (BF= -45455.5454545455).
Then, the model ran, but gave strange looking…