SN74LS688NSR

Overview

The SN74LS688NSR is an 8-bit magnitude and identity comparator manufactured by Texas Instruments. It operates within a supply voltage range of 4.85 V to 5.25 V and features a 20-pin SOIC package. The device provides active-low outputs indicating equality (A=B) or inequality between two 8-bit binary words. Key electrical parameters include a maximum propagation delay of 23 ns at 5 V, a maximum power supply current of 65 mA, and output drive capabilities of -400 µA (high) and 24 mA (low). It functions reliably across an operating temperature range of 0°C to +70°C.

Feature Summary

• Performs 8-bit magnitude comparison and identity checking for digital logic applications
• Provides active-low output signals to indicate when input vectors are equal or unequal
• Utilizes Schottky Low-power (LS) TTL technology for enhanced speed and reduced power consumption

Applications

• Digital data validation circuits requiring equality checks
• Address decoding systems in microprocessor-based designs
• Error detection logic in data transmission paths

Procurement Notes

Verify the specific suffix 'SR' confirms the tape-and-reel packaging format distinct from tube-packaged variants. Confirm the LS logic family designation aligns with system voltage and interface requirements. Ensure the SOIC-20 footprint matches the target PCB layout. Validate that the commercial temperature range meets operational environmental standards.

Selection Notes

Select this component when 8-bit identity comparison is required with low-power dissipation constraints. The LS series offers a balance of speed and power suitable for general-purpose digital systems. Consider the active-low output polarity when designing downstream logic gates. Verify compatibility with existing 5V logic levels in the circuit architecture.

Part Context

This part belongs to the SN74LS688 family of 8-bit comparators. It serves as a functional equivalent to other industry-standard 8-bit identity checkers. The device is designed for integration into larger digital systems requiring reliable binary comparison. It complements other LS-series logic components for comprehensive system design.

Replacement Considerations

Cross-reference with SN74LS688N for tube-packaged equivalents. Verify pinout compatibility with SN74LS688DW for surface-mount alternatives. Ensure logical function matches A=B identity comparison requirements before substitution.