The use of the Fujitsu prefix MB suggests it's a standard-line part. If you're still discussing those quad flat-packs, however, it's not likely it's an EPROM because it would have too few pins to be even a smallish EPROM. Moreover that's an inappropriate package for an EPROM that has to be programmed, considering the handling equipment of the time when these packages were in use. It is probably analog, or may even be some small scratchpad ram or some such. With only 17 pins, it can't be much more than a 1k-bit memory. Both Fujitsu and Hitachi made an extensive array of high-speed memories for mainframes and supercomputers. It could be that you have a really fast 16-bit ECL memory in a package that would make for a nice pair of cuff links or a high-tech tie-tack. A look at their web site might not be a bad idea. Dick ----- Original Message ----- From: Dwight Elvey <elvey(a)hal.com> To: <classiccmp(a)classiccmp.org> Sent: Tuesday, August 01, 2000 6:26 PM Subject: Re[2]: Discontinued IC's: Fairchild (?) MB15604; FPGA? to though logo is Fujitsu