Dan wrote: At one time I had a tube of them, but alas, no longer do. Octopart reveals that one of the parts brokers lists them: http://www.area51esg.com/search-semiconductorss-capacitors-resistors.htm?pa… Good luck actually getting any, though. I haven't tried this particular broker, but none of the ones I've tried in the past would respond to an RFQ. Apparently even $250 per line item isn't enough to interest them. I think the MM57109 was an MM5799 with a particular ROM mask, though that won't help you since no MM5799-labelled part will do what you want. The MM5799 was from National's original COPS family, which predated the COP4xx family. There was a later MM57409 "Super Number Cruncher" that used the same general concept but was not pin or software compatible. It was NMOS rather than PMOS, so it was probably faster than the MM57109. I've never been able to find one, or evidence that it was designed into any products, though some of the brokers claim to have them. Eric