Difference between "common drain" and "open drain"

[gavin23]

Can someone tell me the difference between "open drain" and "common drain". I've seen some datasheets refer to what looks like & operates like an "open drain" output, as a "common drain" output.

Are the terms sometimes used interchangeably?

Thanks,
Gavin

 

[FvM]

"Common drain" is clearly different from open drain. It usually means a source follower while open drain is a special kind of "common source" circuit.

 

[syeda amna]

common drain is voltage folloer having unity voltage gain.
for open drain see this thread;
https://www.edaboard.com/threads/184577/

 

[gavin23]

Thanks guys - that's what I thought based on my web search. I think the data sheet was in error - it called an open drain output a "common drain" even though the functionality and diagram indicated open drain. I wanted to double check here to see if I was missing anything obvious.

-Gavin