74FCT821ASPC

Overview

The National Semiconductor 74FCT821ASPC is a 10-bit bus driver belonging to the FCT logic series. It features true outputs and operates in a CMOS technology package, specifically the PDIP-24 form factor with a 0.300-inch width. The device supports unidirectional data transfer across two ports within a single functional unit. Key electrical characteristics include a maximum operating frequency of 83.3 MHz at nominal supply voltage and a load capacitance rating of 50 pF. The component is designed for high-speed digital applications requiring robust signal integrity.

Feature Summary

• Provides ten-bit unidirectional bus driving capability with true output polarity
• Incorporates power-off disable functionality to isolate outputs during low-power states
• Utilizes Fast CMOS (FCT) technology for enhanced switching speed and performance

Applications

• High-speed parallel data bus interfacing in computer systems
• Buffering signals between microprocessors and memory modules
• Clock distribution networks requiring precise timing control

Procurement Notes

Verify the manufacturer designation carefully, as National Semiconductor assets were acquired by Texas Instruments. Confirm that the specific part number corresponds to the original National Semiconductor production run rather than subsequent TI equivalents. Ensure the PDIP-24 package dimensions match your board layout requirements before finalizing procurement decisions.

Selection Notes

Select this component when designing systems requiring ten-bit wide data paths with fast propagation delays. The FCT series offers superior performance compared to standard LS or ALS logic families. Consider the PDIP-24 package availability if through-hole mounting is mandatory for your assembly process and thermal constraints.

Part Context

This device is part of the broader FCT logic family developed by National Semiconductor. It serves as a critical interface element in legacy and industrial computing architectures. The 74FCT821 variant specifically addresses the need for high-density bus buffering in compact electronic designs requiring reliable signal transmission.

Replacement Considerations

Cross-reference with PI74FCT821CTR from Pericom/Diodes Inc. or P74FCT821CTPC from Pyramid Semiconductor. Verify pin compatibility and electrical specifications against datasheets before substitution.