SN74LS688N

Overview

The SN74LS688N is an 8-bit Identity/Magnitude Comparator manufactured by Texas Instruments. It performs comparisons of two eight-bit binary or BCD words. The device features a single enable input and active low outputs indicating equality (A=B). It operates within a supply voltage range of 4.85 V to 5.25 V, with a maximum power supply current of 65 mA. Propagation delays are specified at 18 ns and 23 ns. The component supports through-hole mounting in a 20-pin PDIP package and functions within an operating temperature range of 0°C to +70°C.

Feature Summary

• Performs 8-bit magnitude and identity comparisons on binary or BCD inputs
• Provides active low output signals when input words are equal
• Includes an enable function for controlled comparison operations

Applications

• Digital system data validation
• Address decoding circuits
• Error detection logic in computing systems

Procurement Notes

Verify the specific datasheet revision and electrical characteristics against the manufacturer's official documentation before integration. Confirm that the 20-pin PDIP package and through-hole mounting requirements align with the target PCB design. Ensure supply voltage constraints between 4.85 V and 5.25 V are strictly maintained for reliable operation within the specified industrial temperature range.

Selection Notes

Select this component for applications requiring precise 8-bit equality checks using standard TTL logic levels. The LS series offers a balance of speed and power consumption suitable for general-purpose digital designs. Consider the 20-pin DIP form factor if prototyping or legacy board compatibility is required. Verify that the active low output polarity matches the downstream logic gate requirements.

Part Context

This part belongs to the SN74LS688 family of 8-bit comparators from Texas Instruments. It is designed for use in digital electronics where binary word comparison is necessary. The LS technology ensures compatibility with standard 5V logic systems while providing defined propagation delays for timing-critical applications.

Replacement Considerations

Check for SN74ALS688N for faster performance variants within the same functional family. Verify pinout compatibility before substituting with other 8-bit comparator ICs from different manufacturers.