The D41256L-80 is a 262,144-bit (256K x 1) Dynamic Random-Access Memory (DRAM) chip manufactured by NEC. It is a type of semiconductor memory that stores each bit of data in a separate capacitor within an integrated circuit. Due to the tendency of capacitors to discharge, DRAM requires periodic refreshing to maintain the stored information.

Applications

• Main Memory in Computers: Used as primary memory in older computer systems.
• Graphics Cards: Employed as memory for graphics processing units (GPUs) in early graphics cards.
• Printers and Scanners: Used for temporary data storage in printers and scanners.
• Industrial Control Systems: Employed in some industrial control equipment for data storage.
• Test and Measurement Equipment: Found in older test and measurement instruments.

Features

• 256K x 1 Organization: Stores 262,144 bits of data.
• Dynamic Refresh: Requires periodic refreshing to maintain data.
• Fast Access Time: 80 ns access time.
• Single 5V Power Supply: Operates from a single 5-volt power supply.
• TTL Compatible Inputs/Outputs: Easy interface with TTL logic circuits.
• Multiplexed Address Inputs: Reduces the number of address pins required.

Benefits

• High Density: Provides a relatively large amount of memory in a single chip.
• Fast Access Time: Enables quick data access for real-time applications.
• Low Cost: Offers a cost-effective memory solution.
• Widely Available: Has been widely used in various applications.

Additional Details

The D41256L-80 utilizes multiplexed address inputs, which means that the row and column addresses are supplied on the same pins at different times. This technique reduces the number of address pins required, allowing for a smaller package size. The DRAM requires a refresh cycle to maintain the data stored in the capacitors. The refresh cycle involves reading and rewriting the data in each memory cell. The -80 suffix indicates an access time of 80 nanoseconds, which is a critical parameter for determining the speed of data retrieval. The datasheet provides detailed information about the refresh requirements, timing parameters, and other electrical characteristics. Although DRAM technology has evolved significantly since the introduction of the D41256L-80, this chip played an important role in the development of computer memory systems. Understanding the characteristics of this older DRAM chip provides insight into the evolution of memory technology.