74ACT521PC

Overview

The onsemi 74ACT521PC is an 8-bit identity comparator within the 74ACT logic series. It features a 20-pin PDIP package and operates on a single-ended input/output configuration. The device functions as a magnitude comparator with active-low outputs indicating equality (A=B). It supports through-hole mounting and provides high drive capability with output currents of ±24 mA. The component is designed for industrial temperature ranges from -40°C to +85°C.

Feature Summary

• Performs 8-bit magnitude comparison with active-low equality output
• Provides high-current single-ended outputs for direct load driving
• Compatible with standard 74ACT logic family voltage levels

Applications

• Digital data bus monitoring systems
• Address decoding circuits in embedded controllers
• Equality checking in arithmetic logic units

Procurement Notes

Verify component status carefully as this part number is listed as obsolete or limited supply by major distributors. Confirm availability of alternative packages such as SC variants if surface mount is required. Ensure compatibility with existing PCB footprints before finalizing procurement plans due to potential discontinuation risks.

Selection Notes

Select this component when an 8-bit identity comparator with through-hole packaging is required. Consider the 74ACT series specifications for speed and power consumption relative to other logic families. Verify that the active-low output polarity aligns with downstream circuit requirements without additional inversion stages.

Part Context

This component belongs to the 74ACT logic family, known for CMOS performance with TTL-compatible inputs. The 74ACT521 specifically addresses identity comparison needs. Related parts include the 74ACT521SC for surface mount applications. The PDIP-20 package distinguishes it from SOIC alternatives while maintaining functional equivalence within the same logic series.

Replacement Considerations

Public confirmed substitute part numbers include CD74ACT04E and SN74ACT04N from Texas Instruments, though these are inverters rather than comparators. Direct functional substitutes should be verified against specific datasheet parameters.