MM74HCT688WMX

Comparators Overview

The MM74HCT688WMX is an 8-bit magnitude comparator manufactured by National Semiconductor, now part of Texas Instruments. It operates within a supply voltage range of 4.5V to 5.5V and features active low outputs indicating when input A equals input B. The device utilizes HCT CMOS technology for compatibility with TTL inputs while maintaining low power consumption, with a quiescent current of 8 µA. It is housed in a 20-SOIC surface-mount package and supports operating temperatures from -55°C to 125°C.

Comparators Feature Summary

• Performs 8-bit magnitude comparison with active low output assertion upon equality detection
• Compatible with standard TTL logic levels due to HCT input structure
• Low quiescent current consumption suitable for power-sensitive applications

Comparators Applications

• Digital data validation circuits requiring equality checks
• Address decoding systems in microprocessor interfaces
• Error detection logic in digital communication protocols

Comparators Procurement Notes

Verify the manufacturer designation carefully, as National Semiconductor assets were acquired by Texas Instruments. Ensure the suffix 'WMX' corresponds to the specific SOIC-20 tape-and-reel packaging variant. Confirm RoHS compliance status and check for obsolescence notices, as legacy parts may have limited availability or be subject to last-time buys depending on current inventory channels.

Comparators Selection Notes

Select this component when an 8-bit identity comparator is required with HCT-compatible inputs. It is appropriate for designs needing active-low equality signals and wide temperature operation. Consider pin-compatible alternatives if different output polarities or package types are preferred. Verify that the 4.5V minimum supply voltage aligns with the system's power rails before integration.

Comparators Part Context

This part belongs to the 74HCT series of high-speed CMOS logic devices originally developed by National Semiconductor. The 74HCT688 specifically implements an 8-bit magnitude comparator function. As a legacy product from National Semiconductor, it is now managed under the Texas Instruments portfolio, retaining its original part numbering but potentially updated manufacturing sources.

Comparators Replacement Considerations

Cross-reference with TI equivalents such as SN74HCT688N or Nexperia 74HCT688 variants. Verify pinout compatibility and electrical specifications match exactly. Check for any changes in propagation delay or output drive strength between the original National Semiconductor version and current replacements.