The MBM27256-20 is a 256K-bit EPROM (Erasable Programmable Read-Only Memory) manufactured by Fujitsu Electronics America, Inc. EPROMs are a type of non-volatile memory that can be erased by exposure to ultraviolet light and then reprogrammed. The “-20” likely refers to the access time (200ns). They were commonly used for storing firmware or program code in older electronic devices.

Applications

• Firmware storage in embedded systems (legacy)
• Program code storage for microcontrollers (legacy)
• Storing lookup tables
• Character generators

Features

• 256K-bit density (32KB)
• Erasable and reprogrammable
• Single 5V power supply
• TTL compatible inputs and outputs
• Fast access time (likely 200ns based on the -20 designation)

Benefits

• Non-volatile memory storage
• Reprogrammable for firmware updates or code modifications
• Easy to interface with microprocessors and microcontrollers
• Reliable data storage

Additional Details

The MBM27256-20 typically comes in a DIP (Dual In-line Package) with a quartz window for UV erasure. To erase the memory, it must be exposed to a UV light source for a specific duration. Refer to the Fujitsu datasheet for precise specifications, including the erasure time, programming voltage, and operating temperature range. This EPROM is primarily found in older electronic equipment.