I think a 1st order RC filter is simple enough that you could argue that "you don't need a DAC" and is what I expected. But when I opened up the post and saw a

I think a 1st order RC filter is simple enough that you could argue that "you don't need a DAC" and is what I expected. But when I opened up the post and saw a 2nd order (probably) Sallen-key (or is this a MFB? I always get my topologies confused...) with a full-bore OpAmp and capacitors up the wazoo... erm... yeah, they're basically hand-building a DAC at this point. --------------- A lot of stuff is wishy-washy definitions anyway. What's the difference from an analog-comparator and a ADC anyway? An analog-comparator is just a 1-bit ADC after all. So a lot of "what is a DAC" exactly is up to opinion around the edges. But if you've got op-amps and signal conditioning, you're getting pretty darn close to "proper DAC" except you know, not as good (ie: cheap, fast, or simple) as a proper professional solution. ------- EDIT: Reread blogpost. It looks like the RC-filter is in fact, being used. The Espressif docs __suggest__ the OpAmp based 2nd-order filter, but the blogpost is strictly with the simple 1st order RC-filter. So yeah, I'd say that RC-filter is "not a DAC", due to being too simple. (It functions as a DAC in this case, but we got to draw the line somewhere).