SN74ALS688N

Comparators Overview

The SN74ALS688N is an 8-bit identity comparator from Texas Instruments' ALS logic family. It performs parallel comparison of two 8-bit binary words, outputting a low signal when the inputs are equal (A=B). The device features totem-pole outputs and operates within a supply voltage range of 4.5 V to 5.5 V. Key electrical parameters include a maximum propagation delay of 20 ns, a maximum supply current of 19 mA, and low-level output current of 24 mA. It is housed in a 20-pin PDIP package with a commercial operating temperature range of 0°C to +70°C.

Comparators Feature Summary

• Performs 8-bit parallel identity comparison with active-low output for equality detection
• Utilizes Advanced Low-power Schottky (ALS) technology for high-speed operation
• Features totem-pole outputs capable of driving standard TTL loads

Comparators Applications

• Digital data validation circuits requiring word-matching verification
• Address decoding systems in microprocessor-based architectures
• Error checking modules in digital communication interfaces

Comparators Procurement Notes

Verify the component matches the specific SN74ALS688N designation rather than generic variants. Confirm the package type is PDIP-20 and the logic family is ALS. Ensure the supplier provides documentation confirming the 0°C to +70°C operating temperature range and 5V nominal supply requirements. Cross-reference manufacturer part numbers to avoid confusion with non-compatible logic families.

Comparators Selection Notes

Select this component when an 8-bit parallel equality check is required with moderate speed and low power consumption. The ALS series offers a balance between speed and power dissipation suitable for general-purpose digital logic. Consider the 20-pin through-hole package if prototyping or legacy board designs necessitate DIP form factors. Verify input compatibility with existing system logic levels before integration.

Comparators Part Context

This part belongs to the SN74ALS688 series of 8-bit identity comparators manufactured by Texas Instruments. It is part of the broader SNx4ALSxx logic family, which utilizes Advanced Low-power Schottky technology. The series is designed for applications requiring efficient parallel data comparison with reduced power consumption compared to standard TTL counterparts.

Comparators Replacement Considerations

Compatible substitutes include other 8-bit identity comparators from the same logic family, such as the SN74LS688, though performance characteristics may differ. Verify pinout compatibility and electrical specifications before substitution. Non-equivalent magnitude comparators should be evaluated carefully as they may offer additional inequality outputs.