The TMS27PC512-2FML is a 512 Kbit (64Kx8) one-time programmable EPROM from Texas Instruments, built for firmware storage in embedded systems that do not require field reprogramming. Its 200 ns access time is the key timing parameter: it defines how fast the memory can deliver data after the address is stable. For a system running a 5 MHz or slower bus clock, 200 ns leaves comfortable margin; at higher clock rates the bus controller must insert wait states or the memory becomes the timing bottleneck. The PQCC32 package is a surface-mount plastic leaded chip carrier, common in through-hole-to-SMT transitions on legacy board designs.
OTP memory: no field updates possible
This is a one-time programmable device — once written, the data is permanent. That makes it a fit for production firmware that is locked at the factory, not for prototypes or field-upgradeable systems. The 64Kx8 density suits microcontroller boot code, lookup tables, or configuration storage where the contents are finalised before board assembly. If your BOM calls for field reprogrammability, you would need a Flash or EEPROM alternative; for a fixed firmware image that will never change, the OTP approach eliminates the risk of accidental erasure and can simplify the supply chain.
Sourcing and lifecycle posture
For BOM planning, this removes the urgency of a forced redesign or lifetime buy.