Parallel EEPROM for legacy 5 V buses
The Microchip AT28C010-12TU-T is a 1 Mbit parallel EEPROM organized as 128K x 8, accessed through a byte-wide asynchronous interface with a 120 ns access time.
120 ns access time — bus timing margin
The 120 ns access time is the key timing parameter for this parallel EEPROM. For a 5 V controller running at 8 MHz to 12 MHz, 120 ns leaves comfortable margin for address decoding, buffer propagation, and setup/hold without wait states. If your system uses a faster bus clock (above 16 MHz), you may need to insert a wait state or switch to a faster parallel EEPROM — but for typical 8-bit and 16-bit legacy designs, 120 ns is the standard sweet spot.
Industrial temperature grade and 5 V supply
The 5 V ±0.5 V supply rail is common in legacy PLCs, motor drives, and base station controllers; it is not compatible with 3.3 V or 1.8 V buses without level translation.
ROHS3 compliant. This means it remains a viable choice for new production builds and long-term BOM planning without the supply-chain urgency of an end-of-life part.