It’s been about a year since we released the completely redesigned Filter Wizard active filter design tool. Since then, many of you have put Filter Wizard through its paces, and have provided us with some very helpful feedback.
We have received many helpful suggestions and critiques, but the one we heard most often was “please add multiple feedback topologies!”
Low-pass Multiple Feedback Active Filter Stage
Multiple feedback circuit topologies can typically squeeze better performance out of your op amp at higher frequencies, and are less susceptible to effects of component tolerance. Multiple feedback filter stages also invert the input signal, while the Sallen-Key Topology in a non-inverting circuit.
A few excellent resources for multiple feedback filter design:
Do you use Multiple Feedback topologies in your design? What are the tradeoffs in your application? (Please use comment section below)
In Filter Wizard, you can select Multiple Feedback topologies by selecting “I want to choose” in the Components Selection screen, and expanding the configuration controls for each stage in your design:
In addition to the design schematics and evaluation board files that are included in the downloaded design files package, we are now including three SPICE simulation-ready netlists. These files are text-base, .cir netlist files, and are intended to run in any simulator that is capable of opening .cir files. There is one file for each simulation type:
- AC analysis with a sinusoidal source
- Transient analysis with a step input source
- Noise analysis