Spec sheet for AD8251 cites nA input bias currents.
I have a rather simple AD8251 simulation running in LTspice (wrapping the AD model) and it is modeling ~4.5uA of input bias current.
Can you attach some files?
How are you measuring?
If you are simulating at temperature, most spice models are only good at 25C.
Follow up on this thread. We can help you if you could share us your simulation file or even just the schematic so that we can check the problem.
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