Single-Supply Twin T Butterworth Low Pass Filter

Problem:
How does a designer make a Twin T low pass Butterworth filter that operates from a Single-Supply?

Solution:
Use the circuit below:



This circuit has a fixed gain of 1 (0 dB).

The designer, if not familiar with the topics, may want to review Coupling Capacitors (Cin in the schematic) and Virtual Grounding (Vcc/2 in the schematic).