AVR-Chat

--- In AVR-Chat@yahoogroups.com, "Roy E. Burrage" <RBurrage@...> wrote:
>
> Here are a couple of application notes
> that show the power MOSFET structure ...

Well, we've drifted off to power MOSFETs here, so I've changed the subject line.  Looking at these applications notes and Fairchild's description of the DMOS process, it seems to me that the diode is caused by the source metalization contacting the P-doped body region.  This is not necessary, it would be easy to avoid, so I conclude that it is done by choice in the same way as connecting source and substrate in the planar process.

I remain unconvinced about the original topic.  Jon says that the descriptions of the MOSFET turning on because the source is pulled low by the drain via the diode is correct, but provides no justification.

Graham.