89C51CC01

It's about the same as open collector. Do you know some electronics?

Jon

Hi Jon,

I'm assuming it's the drain of a FET. I'm trying to understand the purpose of providing an open drain to the outside world. Is the source already connected to ground? Do I connect a load to the drain, then when I want to use the load do I apply a signal to the gate?

Betty

J>

Open drain does mean the open drain of a MOSFET.

Usually, an electronics designer deals with this. The reason I asked is that an explanation will make little sense without some basic understanding of this aspect of electronics. I'm worried about telling you one or two possible answers because there are others, too, and appreciation comes from knowing the electronics not from having someone hand-wave a few possible uses.

But one of the uses is to allow multiple outputs to be connected up where they can operate in a "wire and/or" mode. There are other uses.

I can't tell from the earlier description you gave. An open drain may typically either have the source connected to ground or else to the + supply. More often it's ground, though. Again, there are other possibilities. For example, it is possible (though I very much doubt it here) to provide access to the source externally, as well.

Yes, that's about it.

Jon

This link might answer your question

Joe