So in this particular op-amp (LT1028), the high impedance would cause the op-amp to create more noise? What if I use a fet op-amp that has
10^12 input resistance?The datasheet for this chip provides a table to find the best-suited chips verses input source resistance. This chip is best for
In article , Sven Wilhelmsson wrote: [...]
In this situation, I'd suggest a discrete JEFT such as the 2SK170. At the low frequency end, the noise voltage of the input matters. At higher frequencies, the bias current's noise component matters.
At very high frequencies, the input capacitance will start to matter but I doubt the OP will get to those frequencies with the coil he has suggested.
Also a JFET does not rectify RF like a bipolar. This can add extra noise in bopolar designs.
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