The Mitsubishi M5L27256K-2 is a 262,144-bit (32K x 8) Erasable Programmable Read-Only Memory (EPROM). It was a commonly used non-volatile memory component in embedded systems, industrial equipment, and early computer applications where firmware and program data needed to be stored reliably and occasionally updated.

Applications

• Embedded Systems: Storing firmware for microcontrollers in industrial control systems, consumer electronics, and automotive applications.
• Industrial Equipment: Storing configuration data and control programs in Programmable Logic Controllers (PLCs) and other industrial automation devices.
• Early Computer Systems: Used in early personal computers and workstations to store BIOS (Basic Input/Output System) and other essential system firmware.
• Telecommunications Equipment: Storing configuration data and program code in network routers, switches, and other telecommunications devices.
• Medical Equipment: Used in medical devices to store calibration data and control software.

Features

• 32K x 8-bit Organization: Offers a storage capacity of 262,144 bits, arranged as 32,768 bytes.
• Erasable and Reprogrammable: Can be erased using ultraviolet (UV) light and reprogrammed with new data using an EPROM programmer.
• Non-Volatile Memory: Retains stored data even when power is removed, ensuring data integrity.
• Fast Access Time: Provides a relatively fast access time for quick data retrieval.
• TTL Compatibility: Compatible with Transistor-Transistor Logic (TTL) voltage levels for easy interfacing with other digital circuits.

Benefits

• Flexibility: Allows for convenient updating of firmware and program code through the erase and reprogram capability.
• Reliability: Offers reliable non-volatile storage for critical system data and firmware.
• Cost-Effectiveness: Provided a cost-effective solution for non-volatile memory requirements in various applications during its production period.
• Wide Availability: Readily available from various suppliers when in production, facilitating its integration into different systems.

Additional Details

The M5L27256K-2 typically operates with a +5V power supply. Programming the EPROM requires an EPROM programmer that applies specific voltage levels to the address, data, and control pins. Erasing the EPROM is achieved by exposing the chip to ultraviolet (UV) light through the quartz window on the top of the package. The duration of UV exposure depends on the intensity of the UV light source. It is packaged in a standard DIP (Dual In-line Package) with a quartz window to allow for UV erasure. Modern alternatives like EEPROM and Flash memory have largely replaced this EPROM in newer designs, due to their in-system programmability and higher densities.