At 09:57 PM 5/3/2003 -0700, you wrote: >Spehro Pefhany wrote: > > My recollection is that it was the other way around- Intel introduced the > > first EPROMs as OTP devices (better than mask-programmed) and the quartz- > > window packages came bit later. IIRC, the 1702 was the first EPROM, the > > earlier 1601 was OTP. It was thought that X-rays might be used for erasing > > the memories but that was dropped for some reason (maybe military related). > >The first field-programmable PROMs (no "E") were definitely OTP, but only >because they were based on blowing physical fuses, not on floating gates. >There was no reason to put them into windowed packages. What about the 1601, then? Remember large ROMs at the time, such as the 2513 character generator were MASK programmed- thousands of dollars mask charges, and many weeks lead time. Strange as it seems today, a relatively large capacity programmable chip was a great relief. The TTL ones were relatively fast, and relatively low capacity, and had a relatively large fallout rate in programming. >The floating gate technology was introduced specificially *because* it >could be erased. The programming of the 1702 was considerably more >complicated than the programming for a comparable fuse-based device. Not my recollection. The fuse programming required controlled analog ramp rates at fairly high current, wheras the 1702 just required repetition or something like that, but it's been a while. >It was only much later that customers realized that they could save >considerable amounts of money in production if they could buy the EPROM dice >in plastic, non-windowed packages. This was beneficial to manufacturers >as well, as they could make one kind of die to fill both development and >production needs. There were non-windowed ceramic packages too. ;-) Before windowed ones. Best regards, Spehro Pefhany --"it's the network..." "The Journey is the reward" speff@interlog.com Info for manufacturers: http://www.trexon.com Embedded software/hardware/analog Info for designers: http://www.speff.com -- http://www.piclist.com hint: The PICList is archived three different ways. See http://www.piclist.com/#archives for details.