SN74ALS688DW Equivalent & Substitute Parts

Part Overview

The SN74ALS688DW is an 8-bit magnitude comparator with active low output, manufactured by Texas Instruments in the 74ALS logic series. This component performs identity comparison operations, outputting an active low signal when inputs A and B are equal. The SN74ALS688DW is currently in Last Time Buy status, indicating end-of-life production. Identifying equivalent substitute parts is necessary to ensure design continuity and maintain supply chain reliability for new production runs and long-term inventory planning.

Substiute Parts

SN74ALS688DW

Texas InstrumentsIn Stock: 3119SN74ALS688DW Datasheet

Current PartRFQ

SN74ALS688DWR

Texas InstrumentsIn Stock: 907SN74ALS688DWR Datasheet

MFR RecommendedRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitution eligibility for the SN74ALS688DW is determined by strict equivalence across the following critical parameters:

• Logic Function: 8-bit identity comparator with active low output (A=B)
• Electrical Specifications: Supply voltage 4.5V ~ 5.5V, output currents 2.6mA (high) and 24mA (low), propagation delay 20ns @ 5V with 50pF load
• Package Compatibility: 20-SOIC surface mount package with identical pinout and mechanical dimensions
• Environmental & Compliance: Operating temperature 0°C ~ 70°C, ROHS3 compliance, REACH unaffected status, MSL Level 1

The substitute part must maintain identical electrical performance, pin configuration, and physical form factor to ensure direct replacement without circuit redesign or PCB modification.

Parameter Comparison

Engineering Selection Recommendations

The SN74ALS688DWR is the direct equivalent substitute for the SN74ALS688DW. Both parts are manufactured by Texas Instruments and share identical electrical specifications, logic function, and package configuration. The primary distinction is product status and packaging format: the SN74ALS688DW is in Last Time Buy status with tube packaging, while the SN74ALS688DWR maintains Active product status with tape and reel packaging.

For new designs and ongoing production, the SN74ALS688DWR is the recommended selection due to its active manufacturing status and standard tape and reel packaging format, which aligns with modern assembly processes. Both parts maintain full ROHS3 compliance and REACH unaffected status, ensuring regulatory compliance across applications.

Frequently Asked Questions (FAQ)

Q: Can the SN74ALS688DWR directly replace the SN74ALS688DW without circuit modification?

A: Yes. The SN74ALS688DWR is a direct pin-for-pin and functionally equivalent replacement. All electrical parameters, logic function, and package dimensions are identical. No circuit redesign or PCB layout changes are required.

Q: What is the difference between the SN74ALS688DW and SN74ALS688DWR?

A: The primary differences are product status and packaging format. The SN74ALS688DW is in Last Time Buy status and supplied in tube packaging. The SN74ALS688DWR is in Active production status and supplied in tape and reel format. Electrical specifications and performance are identical.

Q: Why is the SN74ALS688DW marked as Last Time Buy?

A: Last Time Buy status indicates that the manufacturer is discontinuing production of this specific part number. Customers requiring this component should transition to the active equivalent, the SN74ALS688DWR, for future orders and production runs.

Q: Are there any compatibility concerns with the 20-SOIC package?

A: No. Both the SN74ALS688DW and SN74ALS688DWR use the identical 20-SOIC package with 0.295" width and 7.50mm body dimensions. PCB footprints and assembly processes remain unchanged.

Q: Do both parts meet the same compliance standards?

A: Yes. Both the SN74ALS688DW and SN74ALS688DWR are ROHS3 compliant, REACH unaffected, and carry MSL Level 1 (Unlimited) moisture sensitivity rating. Regulatory and environmental requirements are equivalent.