SN74HC688NG4

Overview

The SN74HC688NG4 is an 8-bit identity comparator manufactured by Texas Instruments in a 20-pin DIP package. It performs comparisons of two 8-bit binary or BCD words, providing an active-low output when inputs are equal (A=B). The device operates within a supply voltage range of 2V to 6V and supports propagation delays as low as 36ns at 6V with 50pF load. It features low static current consumption of 8µA and functions reliably across an industrial temperature range of -40°C to +85°C.

Feature Summary

• Performs identity comparison of two 8-bit binary or BCD words
• Provides active-low output signal when input values are identical
• Supports wide supply voltage operation from 2V to 6V
• Features low power consumption with 8µA maximum static current

Applications

• Digital data validation systems requiring equality checks
• Address decoding circuits in microprocessor interfaces
• BCD code verification in display or counting applications
• Logic control systems for conditional branching based on value matching

Procurement Notes

Verify the component suffix 'G4' indicates lead-free and RoHS compliance per Texas Instruments standards. Confirm the package type is 20-DIP (0.300 inch width) for PCB footprint compatibility. Ensure the operating temperature range of -40°C to +85°C meets environmental requirements. Cross-reference the datasheet revision date to confirm electrical characteristics match design specifications.

Selection Notes

Select this part for applications requiring precise 8-bit equality detection with low power consumption. The HC logic family offers high noise immunity and wide voltage tolerance compared to older TTL counterparts. Consider the 20-pin DIP package for through-hole prototyping or legacy board replacements. Verify that the 36ns propagation delay at 6V satisfies timing constraints in the target circuit design.

Part Context

This component belongs to the SN74HC688 series of 8-bit identity comparators. It is part of the broader 74HC logic family, known for CMOS performance with TTL-compatible inputs. The device serves as a digital logic solution for comparing binary or BCD data streams without arithmetic operations, distinct from magnitude comparators that determine greater-than or less-than relationships.

Replacement Considerations

SN74HC688N is a direct equivalent from Texas Instruments. CD74HC688E is a similar alternative from Texas Instruments in a different package. MM74HC688N from onsemi is a comparable part but is marked as obsolete.