SN74LS688NG4

Overview

The SN74LS688NG4 is an 8-bit identity comparator from Texas Instruments, part of the SN54/74LS68x series. It operates within a supply voltage range of 4.75 V to 5.25 V and features a propagation delay of 23 ns at 5 V. The device utilizes a 20-pin PDIP package with through-hole mounting. Electrical characteristics include a maximum low-level output current of 24 mA and a maximum high-level output current of -0.4 mA. It functions in temperatures from 0°C to +70°C.

Feature Summary

• Performs 8-bit identity comparison where the output indicates if input A equals input B
• Provides active-low output via a totem-pole configuration for direct logic interfacing
• Supports cascading operations using dedicated cascade inputs for multi-word comparisons

Applications

• Digital address decoding systems requiring exact match verification
• Data validation circuits checking equality between two 8-bit data streams
• Control logic monitoring for status register comparison tasks

Procurement Notes

Verify the specific ordering suffix against manufacturer documentation to confirm pinout compatibility and electrical specifications. Ensure the procurement channel provides valid traceability for the SN74LS688NG4 designation. Confirm that the component meets RoHS compliance standards as indicated by the NG4 suffix. Cross-reference datasheet revisions to ensure alignment with current design requirements before finalizing orders.

Selection Notes

Select this component when an 8-bit identity check is required within standard LS TTL logic families. The SN74LS688NG4 offers a cost-effective solution for applications needing precise equality detection without magnitude differentiation. Consider the 20-pin DIP package for prototyping or legacy board designs requiring through-hole assembly methods compatible with standard manufacturing processes.

Part Context

This component belongs to the Texas Instruments SN54/74LS68x family of 8-bit magnitude and identity comparators. The LS series ensures compatibility with standard transistor-transistor logic interfaces while maintaining defined power consumption levels. The device serves as a fundamental building block for digital systems requiring parallel data comparison capabilities across multiple bits simultaneously.

Replacement Considerations

The SN74LS688N serves as a non-RoHS equivalent. Verify functional parity regarding pin assignments and electrical limits before substitution. Check for any differences in propagation delay or output drive strength between the NG4 variant and standard LS counterparts to ensure circuit stability.