SN74HC646DW Equivalent & Substitute Parts

Part Overview

The SN74HC646DW is a non-inverting transceiver IC manufactured by Texas Instruments, designed for 8-bit data transmission with 3-state output capability. Operating across a 2V to 6V supply range, this component is classified as Last Time Buy status, indicating limited future availability. The need for equivalent and substitute parts arises from inventory constraints and the transition to active product lines that maintain identical or compatible electrical and mechanical specifications.

Substiute Parts

SN74HC646DW

Texas InstrumentsIn Stock: 2409SN74HC646DW Datasheet

Current PartRFQ

SN74HC646DWR

Texas InstrumentsIn Stock: 3982SN74HC646DWR Datasheet

MFR RecommendedRFQ

74HC86D,653

Nexperia USA Inc.In Stock: 271374HC86D,653 Datasheet

MFR RecommendedRFQ

SN74HC652DW

Texas InstrumentsIn Stock: 1134SN74HC652DW Datasheet

Parametric EquivalentRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitution for the SN74HC646DW is determined by strict alignment of the following critical parameters:

Primary Substitution Criteria:

• Logic Type: Transceiver, Non-Inverting
• Number of Elements: 1
• Number of Bits per Element: 8
• Output Type: 3-State
• Current - Output High, Low: 7.8mA, 7.8mA
• Voltage - Supply: 2V ~ 6V
• Package / Case: 24-SOIC (0.295", 7.50mm Width)
• Mounting Type: Surface Mount
• RoHS Status: ROHS3 Compliant
• Moisture Sensitivity Level (MSL): 1 (Unlimited)

Substitute Categories:

MFR Recommended Substitute (Packaging Variant): SN74HC646DWR maintains identical electrical specifications and package footprint but differs in packaging format (Tape & Reel vs. Tube). This substitute is preferred for active procurement due to Active product status.

Parametric Equivalent: SN74HC652DW shares the same electrical performance envelope, package dimensions, and compliance certifications. The base product number differs (74HC652 vs. 74HC646), but all critical operating parameters remain equivalent for circuit-level substitution.

Cross-Functional Alternative: 74HC86D,653 (Nexperia USA Inc.) operates within the same voltage supply range and compliance framework but serves a different logic function (XOR gate). This part is listed as a functional alternative only when circuit topology permits XOR logic substitution.

Parameter Comparison

Engineering Selection Recommendations

For Direct Pin-Compatible Substitution:

SN74HC646DWR is the primary recommended substitute. It maintains 100% electrical equivalence with the original SN74HC646DW while offering Active product status, ensuring long-term availability and supply chain stability. The only difference is packaging format (Tape & Reel vs. Tube), which does not affect circuit performance or PCB assembly compatibility.

For Parametric Equivalence:

SN74HC652DW provides full functional substitution when the base product number change is acceptable within design documentation. All critical electrical parameters, package footprint, and compliance certifications remain identical to the SN74HC646DW. This part is suitable for new designs or redesigns where component qualification is feasible.

For Compliance and Regulatory Alignment:

All substitute parts maintain ROHS3 compliance and MSL Level 1 (Unlimited) moisture sensitivity rating, ensuring compatibility with standard manufacturing and storage protocols. No additional handling or environmental controls are required when transitioning between these parts.

Regarding 74HC86D,653:

This part is not recommended as a direct substitute due to functional incompatibility (XOR logic vs. Transceiver logic). Selection of this part requires circuit topology redesign and is only applicable in specialized applications where XOR functionality replaces transceiver functionality.

Frequently Asked Questions (FAQ)

Q: Can SN74HC646DWR be used as a direct replacement for SN74HC646DW?

A: Yes. SN74HC646DWR is electrically and mechanically identical to SN74HC646DW. The difference is packaging format: SN74HC646DWR is supplied in Tape & Reel format while SN74HC646DW is supplied in Tube format. Both are surface-mount 24-SOIC packages with identical pin configurations and electrical performance.

Q: What is the difference between SN74HC646DW and SN74HC652DW?

A: Both parts are non-inverting transceivers with 8-bit elements, 3-state outputs, and identical electrical specifications (7.8mA output current, 2V-6V supply, -40°C to 85°C operating range). The base product numbers differ (74HC646 vs. 74HC652), but all critical parameters that determine circuit substitution are equivalent. Both use 24-SOIC packaging.

Q: Why is 74HC86D,653 listed as a substitute if it is not directly compatible?

A: 74HC86D,653 is listed as a cross-functional alternative based on shared voltage supply range (2V-6V) and compliance certifications (ROHS3, MSL Level 1). However, it performs XOR logic rather than transceiver logic and uses a different package (14-SOIC vs. 24-SOIC). This part is only applicable when circuit design permits functional substitution of logic gates.

Q: Are there any temperature range limitations when substituting these parts?

A: SN74HC646DW, SN74HC646DWR, and SN74HC652DW all operate across -40°C to 85°C. The 74HC86D,653 extends to -40°C to 125°C. If your application requires operation above 85°C, only the 74HC86D,653 meets this requirement, but functional compatibility must be verified independently.

Q: Do all substitute parts meet the same RoHS and moisture sensitivity requirements?

A: Yes. All listed parts are ROHS3 compliant and rated MSL Level 1 (Unlimited). No additional environmental controls or handling procedures are required when transitioning between these parts.

Q: Which substitute should I select for new production orders?

A: SN74HC646DWR is the recommended choice for new production due to Active product status and guaranteed long-term availability. It provides identical electrical and mechanical performance to the original SN74HC646DW with superior supply chain continuity.