SN74LS688NS

Overview

The SN74LS688NS is an 8-bit magnitude and identity comparator from Texas Instruments, housed in a 20-pin SOIC surface-mount package. It operates within a supply voltage range of 4.75 V to 5.25 V. The device features a propagation delay of 23 ns at 5 V with a 45 pF load. Output characteristics include a maximum low-level output current of 24 mA and a high-level output current of -0.4 mA. The component supports through-hole or surface-mount installation styles depending on the specific variant configuration, with an operating temperature range of 0°C to +70°C.

Feature Summary

• Performs 8-bit magnitude comparison and identity checking functions
• Provides active-low output indication when input conditions are met
• Utilizes Schottky logic technology for enhanced switching speed

Applications

• Digital data validation circuits
• Address decoding systems
• Error detection logic in digital processors

Procurement Notes

Verify the exact suffix designation as datasheets may list SN74LS688N (PDIP) while distributors reference SN74LS688NS (SOIC). Confirm RoHS compliance status and check for obsolete status notifications, as some variants like SN74LS688NSR are marked as no longer manufactured. Ensure the selected package matches the PCB footprint requirements before ordering.

Selection Notes

Select this component for applications requiring fast 8-bit comparison in standard TTL-compatible environments. Consider the SN74ALS688 series if lower power consumption and faster propagation delays are required. Verify that the 5V supply voltage aligns with the system design constraints and that the surface-mount package fits the assembly capabilities.

Part Context

This part belongs to the Texas Instruments SN74LS688 family of 8-bit comparators. It is functionally related to the SN74LS688N (PDIP version) and shares core logical operations. The LS series indicates Low-power Schottky logic, offering a balance between speed and power dissipation compared to standard TTL devices.

Replacement Considerations

Public confirmed substitutes include SN74LS688NE4 and SN74ALS688N. Note that SN74LS688NSR is listed as obsolete by some manufacturers.