DP8421AVX-20

Controllers Overview

The DP8421AVX-20 is a microCMOS programmable dynamic RAM controller designed for 1 Mbit DRAM arrays. It provides a single-chip interface between DRAM and 8-, 16-, or 32-bit systems, generating all necessary access control signal timing. The device features an on-chip refresh request clock for automatic array refreshing and handles arbitration between refreshes and accesses. It includes high capacitance drivers for RAS, CAS, WE, and DRAM address outputs, along with an on-chip high precision delay line to guarantee critical timing parameters.

Controllers Feature Summary

• Integrates high capacitance drivers for RAS, CAS, WE, and DRAM address signals to support direct connection to memory arrays without external buffering logic.

Controllers Applications

• Interface between dynamic RAM and 8-bit system buses
• Interface between dynamic RAM and 16-bit system buses
• Interface between dynamic RAM and 32-bit system buses

Controllers Procurement Notes

Verify the component status as obsolete before procurement planning. Confirm that the specific suffix 'VX' corresponds to the required package and temperature grade by cross-referencing the manufacturer's official documentation, as ordering suffixes define physical attributes rather than functional changes.

Controllers Selection Notes

Select this controller when interfacing with 1 Mbit DRAMs requiring a single access port. Ensure the system design accommodates the requirement for an external hardware reset prior to programming. Verify that the DELCLK input frequency adheres to the specified multiples of 2 MHz to maintain internal delay line accuracy.

Controllers Part Context

This part belongs to the DP8420A/21A/22A family of microCMOS programmable DRAM controllers. While the DP8420A supports 256 kbit and the DP8422A supports 4 Mbit with dual ports, the DP8421A specifically targets 1 Mbit capacity with a single access port architecture.

Controllers Replacement Considerations

Public confirmed substitute part numbers are not available in the provided source material.