1 Mbit parallel EPROM — 200 ns access, military temp, ceramic DIP
The Cypress CY27C010-200WMB is a 1 Mbit (128K x 8) parallel EPROM with a 200 ns access time, packaged in a 28-lead CERDIP for through-hole mounting. As a UV-erasable programmable read-only memory, it serves as the firmware store in legacy high-reliability systems — avionics, satellite, missile guidance, and downhole instrumentation — where the ceramic hermetic seal and wide temperature tolerance are non-negotiable.
The 200 ns access time sets the read-cycle timing for the host CPU or state machine. At 4.5 V, the part drives data onto the bus within 200 ns of address valid.
28-lead CERDIP — rework and reliability
It handles repeated UV erasure cycles without degradation — the quartz window is integral to the EPROM process. For rework, the through-hole leads are straightforward to desolder with a hot-air station or solder pot; the ceramic body tolerates higher thermal stress than plastic. Pin 1 is marked by a notch on the package end — verify orientation before insertion.