I have been reading about "Zero impedance line outputs" where the output capacitor is in the feedback loop of an opamp by means of multiple resistive paths back to the non-inverting input.
The issue is that the stage seems necessarily need gain to function, how would one go about including the output capacitor and 50 ohm isolating resistor in a non-inverting voltage follower?
Just take the feedback from the output side of the capacitor?
The issue is that the stage seems necessarily need gain to function, how would one go about including the output capacitor and 50 ohm isolating resistor in a non-inverting voltage follower?
Just take the feedback from the output side of the capacitor?
Unity gain buffers don't normally need capacitive coupling, as any input-offset isn't multiplied up, and many modern opamps have input offsets < 1mV...
Zero impedance outputs normally means the output side of the output resistor has a separate low-frequency feedback path. https://groupdiy.com/threads/zero-impedance-output.52076/ Of course you need the high-frequency feedback path as well for stability if the output is capacitively loaded.
BTW don't be confused by the circuit in that thread - the RHS is injecting a signal into the output to measure the output impedance, the large capacitor is part of the measurement circuit, not the buffer.
Zero impedance outputs normally means the output side of the output resistor has a separate low-frequency feedback path. https://groupdiy.com/threads/zero-impedance-output.52076/ Of course you need the high-frequency feedback path as well for stability if the output is capacitively loaded.
BTW don't be confused by the circuit in that thread - the RHS is injecting a signal into the output to measure the output impedance, the large capacitor is part of the measurement circuit, not the buffer.