Dear AD Engineers,
In order to construct device for measurements in condensed matter physics we analyze different filters.
We search a modern operational amplifier for usage in Generalized Impedance Converter (GIC).
Looking in AD collection of dual operational amplifiers, we found the following models to have application in GIC topologies (as filters) in their specifications: AD712, OP275, OP285, AD8542
Particularly in OP285/OP275 we read the following sentence:
“The closely matched and uniform ac characteristics of the OP285 make it ideal for use in GIC (Generalized Impedance Converter) and FDNR (Frequency Dependent Negative Resistor) filter applications.”
Our question is -- which are the most important parameters of an operational amplifier that makes it ideal or at least suitable in GIC and FDNR filter applications?
“The AD712 is ideally suited to drive high speed ADCs because it offers both wide bandwidth and high open-loop gain.”
“The circuit in Figure 46 uses a 100 Ω isolation resistor that enables the amplifier to drive capacitive loads exceeding 1500 pF; the resistor effectively isolates the high frequency feedback from the load and stabilizes the circuit.”
“Thus designed, the AD712 settles to ±0.01%, with a 10 V output step, in under 1 μs, while retaining the ability to drive a 250 pF load capacitance when operating as a unity-gain follower.”
Also, could you please point out at least one modern (introduced in the last 10 years) operational amplifier for such usage?
The newest of the mentioned operational amplifiers above was launched in 2003 according to its first documentation revision.
Thank you in advance for the cooperation.