Any ideas why almost all mosfets have the source and substrate (body)
internally attached? There is no fundamental reason why this needs to be
(mosfets on ICs often do not do this), and it would allow you to
(optionally) eliminate the body diode. The fet would be totally
symmetrical with respect to source and drain, as long as you kept the
body terminal tied to the lowest potential in the circuit (highest for
Pmos). Since many fets come in to-220 packages, they could easily make
the tab the body (or keep the tab as the drain and make the drain pin the
body).

Sean


 On Fri, 14 Feb 2003, Russell McMahon wrote:

> What people make and sell is the ultimate arbiter (alas) of what you have to
> do to make them work. Current MOSFETS are sold as 2 quadrant devices at
> present (ie gate with one polarity, drain with either) and the 2nd quadrant
> is not overly useful in most cases due to the body diode.
>
>
>
>             Russell McMahon
>
> --
> http://www.piclist.com hint: The PICList is archived three different
> ways.  See http://www.piclist.com/#archives for details.
>

--
http://www.piclist.com hint: The PICList is archived three different
ways.  See http://www.piclist.com/#archives for details.