74AC521SC

Overview

The onsemi 74AC521SC is an 8-bit identity comparator integrated circuit belonging to the 74AC logic series. It operates within a supply voltage range of 4.5V to 5.5V and features active low outputs that indicate equality between two 8-bit inputs. The device provides high drive capability with output currents of 24mA for both high and low states, while maintaining a quiescent current of only 4 µA. It exhibits a maximum propagation delay of 10ns at 5V with a 50pF load. Packaged in a 20-SOIC surface-mount case, it supports an operating temperature range from -40°C to +85°C.

Feature Summary

• Performs 8-bit magnitude comparison to determine if input A equals input B
• Provides active low output signaling for identity verification
• Delivers strong 24mA sink and source output drive capability
• Operates with low quiescent current consumption

Applications

• Digital data bus monitoring systems
• Address decoding circuits
• Data validation logic in embedded controllers

Procurement Notes

Verify component authenticity through authorized channels as this part is officially marked obsolete by the manufacturer. Confirm package integrity and pin alignment against the 20-SOIC specification before integration. Review available replacement options due to end-of-life status. Ensure design updates account for the discontinuation of this specific onsemi part number.

Selection Notes

Select this component when an 8-bit identity comparison function is required within standard 5V CMOS logic environments. The 74AC series offers faster switching speeds compared to HC variants while maintaining compatible pinouts. Consider the 20-SOIC package constraints and thermal requirements for your PCB layout. Evaluate alternative active parts if long-term supply stability is critical for production.

Part Context

This device is part of the broader 74ACT/74AC family of logic comparators manufactured by onsemi. It serves as a digital logic solution for comparing binary values in industrial and consumer electronics. The 74AC521 specifically addresses applications requiring parallel data equality checks without complex microprocessor intervention.

Replacement Considerations

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