>
> OTP is PROM, which is an EPROM with no window.

Actually these are not equivalent. A PROM cell has no mechanism for reversing
state once the cell has been blown. A EPROM cell can be regenerated by
exposure to UV. Even though in an OTP the EPROM is covered, nevertheless
they are EPROM cells, which are different that PROM ones....


>
> The pattern 'blown' into a ROM is done with metalisation layers during the
> final stages of production, which means that you have to commit to a lot of
> parts.
>
> Rgds...
>
> ...Andy
>
> At 13:32 17/02/99 -0500, you wrote:
> >I just rec'd the new Microchip line card. Inside they have a new
> >category of parts classified as "R" such as 12CR509. The only
> >difference they show is that the "R" version is classified as  ROM
> >where the others are listed as OTP/Flash. Many of course are not
> >flash. OTP is ROM, so what are they getting at here? Or is this just
> >another way to classify window parts?
> >
> >Thanks
> >Jack Shidemantle
> >Automation & Development Engineer
> >YSI, Inc. USA
> >
>