MM74HC688WM

Comparators Overview

The MM74HC688WM is an 8-bit magnitude comparator from the Fairchild Semiconductor 74HC series, housed in a 20-pin SOIC-Wide package. It functions as an equality detector, comparing two 8-bit binary words to determine if they are identical. Key electrical specifications include a maximum propagation delay of 30ns at 6V with 50pF load, output high/low currents of 5.2mA each, and quiescent current of 8µA. The device operates within a voltage range of 2V to 6V and supports an operating temperature range of -40°C to 85°C.

Comparators Feature Summary

• Performs 8-bit magnitude comparison for equality detection
• Compatible with standard CMOS logic families
• Wide supply voltage operation range
• Industrial temperature grade availability

Comparators Applications

• Memory block decoding applications
• Generating memory block enable signals from computer address information
• Digital system equality checking

Comparators Procurement Notes

Verify the manufacturer origin, as Fairchild Semiconductor assets were acquired by onsemi. Confirm the specific suffix 'WM' corresponds to the SOIC-Wide package and industrial temperature range (-40°C to 85°C). Ensure compatibility with existing PCB footprints for the 20-pin wide SOIC format before procurement.

Comparators Selection Notes

Select this component when an 8-bit parallel equality check is required in HC-series logic designs. Consider the 30ns propagation delay and 5.2mA drive capability against system timing requirements. Verify that the 2-6V supply range aligns with the target circuit's power rails and that the SOIC-Wide package fits the assembly constraints.

Comparators Part Context

This part belongs to the 74HC family of high-speed CMOS logic devices. It is functionally equivalent to other 8-bit comparators like the 74HC688 but is specifically packaged in the wider SOIC variant. The device serves as a fundamental building block for digital decision-making circuits requiring direct binary word comparison without intermediate processing.

Comparators Replacement Considerations

The Nexperia 74HC688D,653 is a documented alternative offering similar 8-bit magnitude comparison functionality in a standard SOIC-20 package. Verify pinout compatibility and ensure the replacement meets the required -40°C to 85°C operating temperature range.