74FCT521APC

Overview

The 74FCT521APC is an 8-bit identity comparator manufactured by National Semiconductor. It features active low outputs indicating equality (A=B) between two 8-bit inputs. The device operates within a supply voltage range of 4.75 V to 5.25 V, with a maximum power supply current of 4.5 mA. Propagation delays are specified at 6 ns and 7.2 ns. It functions reliably across a temperature range of -40°C to +85°C and is housed in a 20-pin PDIP package.

Feature Summary

• Performs high-speed comparison of two 8-bit binary words
• Provides active low output signal when input vectors are identical
• Compatible with standard FCT logic families for system integration

Applications

• Microprocessor address matching circuits
• Memory controller data validation
• Digital system error detection logic

Procurement Notes

Verify the specific manufacturer designation, as National Semiconductor assets were acquired by Texas Instruments. Confirm that the 20-PDIP package matches your board layout requirements. Ensure the operating temperature range meets your environmental specifications before finalizing procurement orders.

Selection Notes

Select this component when an 8-bit identity check is required with active low signaling. The FCT technology offers faster switching speeds compared to standard TTL. Consider the PDIP package size for through-hole mounting constraints and verify voltage compatibility with existing 5V logic systems.

Part Context

This part belongs to the 74FCT series of fast CMOS logic devices. It serves as a specialized comparator within digital logic families, distinct from general-purpose arithmetic units. The device provides dedicated hardware acceleration for equality checks in complex digital architectures.

Replacement Considerations

The 74F521PC is a documented equivalent variant from the same manufacturer lineage. Verify pinout compatibility and electrical characteristics when substituting components in existing designs.