74LVC646ADB,118 Equivalent & Substitute Parts

Part Overview

The 74LVC646ADB,118 is a non-inverting transceiver IC manufactured by NXP USA Inc., designed for 8-bit bidirectional data transfer with 3-state output capability. Operating across a supply voltage range of 1.2V to 3.6V, this component is classified as obsolete, making equivalent and substitute parts necessary for ongoing design support and procurement.

The 74LVC series transceiver architecture provides low-voltage CMOS logic switching with controlled output impedance, suitable for bus interface and signal buffering applications. Substitution is driven by product lifecycle status and the need for active, readily available alternatives that maintain functional and electrical compatibility.

Substiute Parts

74LVC646ADB,118

NXP USA Inc.In Stock: 81374LVC646ADB,118 Datasheet

Current PartRFQ

SN74LVTH652PW

Texas InstrumentsIn Stock: 1196SN74LVTH652PW Datasheet

DirectRFQ

SN74LVC646ADBR

Texas InstrumentsIn Stock: 26359SN74LVC646ADBR Datasheet

MFR RecommendedRFQ

SN74LVC646APW

Texas InstrumentsIn Stock: 1211SN74LVC646APW Datasheet

MFR RecommendedRFQ

SN74LVC646APWR

Texas InstrumentsIn Stock: 859SN74LVC646APWR Datasheet

MFR RecommendedRFQ

SN74LVC646APWT

Texas InstrumentsIn Stock: 899SN74LVC646APWT Datasheet

MFR RecommendedRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitution of the 74LVC646ADB,118 is determined by the following critical parameters:

Functional Equivalence Criteria:

• Logic type: Transceiver, Non-Inverting
• Number of elements: 1
• Number of bits per element: 8
• Output type: 3-State

Electrical Compatibility Criteria:

• Output current capability: 24mA minimum (High and Low)
• Supply voltage range: Must support 1.2V to 3.6V operation or a subset thereof
• Operating temperature range: -40°C to 125°C preferred; -40°C to 85°C acceptable for most applications

Package Compatibility Criteria:

• Primary package: 24-SSOP (0.209", 5.30mm Width)
• Alternative package: 24-TSSOP (0.173", 4.40mm Width) with PCB layout modification

Substitute parts are grouped into two categories:

Category 1: Direct Functional Equivalents (Same Base Product Number) Parts sharing the 74LVC646 base product number with active product status and identical electrical specifications.

Category 2: Cross-Series Alternatives Parts from the 74LVTH series offering enhanced output current capability (32mA/64mA) with reduced supply voltage floor (2.7V minimum) and narrower operating temperature range (-40°C to 85°C).

Parameter Comparison

Engineering Selection Recommendations

Primary Recommendation: SN74LVC646ADBR

The SN74LVC646ADBR is the manufacturer-recommended direct substitute. It maintains identical electrical specifications (24mA output current, 1.65V to 3.6V supply range) and package form factor (24-SSOP, 0.209" width) as the original 74LVC646ADB,118. Product status is active with 26,346 units in stock. This part requires no PCB layout modification and provides the most straightforward replacement path. The reduced supply voltage floor (1.65V vs. 1.2V) is acceptable for standard 3.3V and lower voltage applications.

Secondary Recommendation: SN74LVC646APW or SN74LVC646APWR

These parts offer identical electrical performance to the SN74LVC646ADBR but in 24-TSSOP packaging (0.173" width). Selection between APW (Tube packaging) and APWR (Tape & Reel packaging) depends on procurement volume and handling requirements. PCB layout modification is required to accommodate the narrower package footprint. Both maintain active product status with adequate inventory availability.

Alternative for Enhanced Output Drive: SN74LVTH652PW

The SN74LVTH652PW provides increased output current capability (32mA high, 64mA low) compared to the 74LVC646 series. This part is suitable for applications requiring higher drive capability or lower output impedance. The supply voltage floor increases to 2.7V, making it unsuitable for applications requiring operation below 2.7V. Operating temperature range is -40°C to 85°C. Package is 24-TSSOP, requiring PCB layout modification.

All recommended substitutes maintain ROHS3 compliance, MSL Level 1 rating, and EAR99 export classification consistent with the original part.

Frequently Asked Questions (FAQ)

Q: Can the SN74LVC646ADBR be used as a direct drop-in replacement for the 74LVC646ADB,118?

A: Yes. The SN74LVC646ADBR is electrically and mechanically compatible with identical package form factor (24-SSOP). No PCB layout modification is required. The reduced supply voltage floor (1.65V vs. 1.2V) does not affect standard 3.3V or lower voltage applications operating above 1.65V.

Q: What is the difference between SN74LVC646APW and SN74LVC646APWR?

A: Both parts are electrically identical. The difference is packaging format: APW is supplied in Tube packaging for smaller quantities, while APWR is supplied in Tape & Reel format for higher volume production. Select based on procurement volume and assembly line requirements.

Q: Why does the SN74LVTH652PW have higher output current specifications?

A: The 74LVTH series uses a different internal circuit topology optimized for higher output drive capability. The 32mA high and 64mA low output currents provide lower output impedance compared to the 24mA symmetric output of the 74LVC646 series. This is beneficial for applications requiring faster edge rates or driving heavily loaded buses.

Q: Can I use SN74LVTH652PW in applications requiring operation below 2.7V?

A: No. The SN74LVTH652PW minimum supply voltage is 2.7V. If your application requires operation at 1.2V to 2.6V, use the SN74LVC646ADBR or SN74LVC646APW/APWR variants, which support down to 1.65V.

Q: What PCB layout modifications are needed when switching from 24-SSOP to 24-TSSOP packaging?

A: The 24-TSSOP package is narrower (0.173" vs. 0.209" width). Footprint dimensions, pad spacing, and via placement must be updated in the PCB design. Consult the respective Texas Instruments datasheets for detailed package drawings and land pattern specifications. No electrical modifications are required.

Q: Are all substitute parts RoHS3 compliant?

A: Yes. All recommended substitute parts (SN74LVC646ADBR, SN74LVC646APW, SN74LVC646APWR, and SN74LVTH652PW) are ROHS3 compliant with MSL Level 1 rating, matching the original 74LVC646ADB,118 compliance status.

Q: What is the operating temperature difference between the original part and substitutes?

A: The original 74LVC646ADB,118 operates from -40°C to 125°C. All Texas Instruments substitutes operate from -40°C to 85°C. If your application requires operation above 85°C, the original part or equivalent high-temperature variants must be sourced. For standard industrial and commercial temperature ranges (-40°C to 85°C), all substitutes are fully compatible.