I've designed a simple non-inverting amplifier to interface a 3.3V MCU and a 5V signal to a motor controller. When I first tested with the MCU and the desired values to the low-pass filter, I noted that something was strange. This way, I decided to perform a test using the circuit below, where the PWM is from an Arduino.
The table below shows my results:
I tried swaping the PWM + filter for a 1k pot but the results were similar. I also tried swaping the multimeter and the op amp, nothing changes. Some tip why I'm having this behavior in this circuit?