DP8421AVX-25

Controllers Overview

The DP8421AVX-25 is a microCMOS programmable dynamic RAM controller designed for 1M-bit 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 includes high capacitance drivers for RAS, CAS, WE, and address lines. It supports byte writing via on-chip enable signals and offers selectable controller speeds of 20 MHz and 25 MHz.

Controllers Feature Summary

• On-chip high precision delay line ensures critical DRAM access timing parameters are met.
• Integrated arbitration logic manages refresh cycles and system accesses without external intervention.
• Programmable configuration allows support for nibble, page, and static column DRAM operations.
• High capacitive drivers reduce the need for external buffering on control and address lines.

Controllers Applications

• Interface between microprocessors and 1M-bit dynamic RAM arrays
• Systems requiring automatic DRAM refresh management
• Embedded designs utilizing 8-, 16-, or 32-bit bus architectures

Controllers Procurement Notes

Verify component authenticity through authorized distributors or direct manufacturer channels. Confirm package integrity and pin alignment against the PLCC-68 specification. Review datasheet revision history for any functional updates. Ensure environmental compliance documentation matches project requirements. Validate that the specific suffix corresponds to the intended speed grade and temperature range.

Controllers Selection Notes

Select this controller when interfacing with 1M-bit DRAMs in 8-, 16-, or 32-bit systems. Choose based on required memory density and bus width compatibility. Consider the 25 MHz speed option for higher performance needs. Evaluate the need for on-chip arbitration and byte-enable features to simplify board layout. Verify power supply constraints align with the microCMOS process characteristics.

Controllers Part Context

This component belongs to the DP8420A/21A/22A family of programmable DRAM controllers. The DP8421A variant specifically targets 1M-bit memory configurations, distinguishing it from the 256k-bit DP8420A and the dual-port 4M-bit DP8422A. All members share common programming methods and core timing generation logic.

Controllers Replacement Considerations

Public confirmed substitute part numbers only; omit otherwise.