[TriEmbed] PWM to Analog 0 to 5 VDC?

Martin Brooke martin.brooke at duke.edu
Tue Jun 30 11:27:24 CDT 2020

Use this website to design an active filter

Here is what I would use unless you need fast response

 Sallen-Key Low-pass Filter Design Tool - Result...

Uses 2 x 1 Megohm resistors and 2 x 0.1 uF capacitors

Super stable output probably from most normal PWM, but not very fast.  The
signal stable in about a second after the PWM changes.

Use this opamp:


it is $0.33  for 1 they have thousands in stock today.  Digikey ships fast
by low cost USPS to RDU area, typically 2-day to my home!

The DIP package makes it easy to use with a protoboard.

But any CMOS opamp with Rail to rail input and output performance and 5V
single supply operation should work.

There are other circuits that are similar


that let you adjust performance more but probably not worth it.

If you do not have a 5V power supply you might try this


to generate close to 5V power from your incoming PWM signal.  With a large
enough capacitor it probably will work if the PWM source is strong.


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