74LCX646WMX Equivalent & Substitute Parts

Part Overview

The 74LCX646WMX is a non-inverting transceiver IC manufactured by onsemi, designed for 8-bit bidirectional data transfer with 3-state output capability. Operating across a 2V to 3.6V supply voltage range, this component is classified as obsolete, making equivalent substitute parts necessary for new designs and ongoing production requirements. The 24-SOP package configuration and specific electrical characteristics define the substitution criteria for compatible alternatives.

Substiute Parts

74LCX646WMX

onsemiIn Stock: 312174LCX646WMX Datasheet

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SN74LVC646ADW

Texas InstrumentsIn Stock: 1302SN74LVC646ADW Datasheet

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SN74LVC646APW

Texas InstrumentsIn Stock: 1211SN74LVC646APW Datasheet

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Key Parameters

Substitute Part Grouping Explanation

Substitution for the 74LCX646WMX is determined by the following critical parameters:

• Logic Function: Transceiver, Non-Inverting with 1 Element and 8 Bits per Element
• Output Configuration: 3-State output capability
• Electrical Performance: 24mA output current (high and low)
• Supply Voltage Compatibility: Operating range must accommodate the 2V to 3.6V specification
• Package Compatibility: Surface mount configuration with matching pin count and footprint dimensions
• Operating Temperature Range: -40°C to 85°C (TA)

The substitute parts identified (SN74LVC646ADW and SN74LVC646APW) maintain identical logic function, bit configuration, output type, and electrical current specifications. Both are manufactured by Texas Instruments and feature active product status with RoHS3 compliance. Substitution is valid when the supply voltage range of the substitute encompasses the original specification and package dimensions remain compatible with the PCB layout.

Parameter Comparison

Engineering Selection Recommendations

SN74LVC646ADW is the primary substitute for direct replacement of the 74LCX646WMX. Both components utilize identical 24-SOIC packaging with matching footprint dimensions (0.295", 7.50mm width), enabling direct PCB layout compatibility without redesign. The SN74LVC646ADW maintains active product status with RoHS3 compliance, ensuring long-term availability and regulatory alignment for new production.

SN74LVC646APW provides functional equivalence with identical electrical specifications and logic performance. However, this variant uses 24-TSSOP packaging (0.173", 4.40mm width), which differs from the original 24-SOIC footprint. Selection of the SN74LVC646APW requires PCB layout modification to accommodate the smaller package dimensions. This option is suitable for space-constrained applications where package size reduction is beneficial.

Both Texas Instruments substitutes feature expanded supply voltage ranges (1.65V to 3.6V) that fully encompass the original 2V to 3.6V specification, providing enhanced flexibility in power supply design. Active product status and RoHS3 compliance support long-term design viability and regulatory requirements.

Frequently Asked Questions (FAQ)

Q: Can the SN74LVC646ADW directly replace the 74LCX646WMX without PCB modification?

A: Yes. Both components share identical 24-SOIC packaging dimensions (0.295", 7.50mm width), enabling direct footprint compatibility and pin-for-pin replacement without PCB redesign.

Q: What is the primary difference between the two Texas Instruments substitutes?

A: The SN74LVC646ADW uses 24-SOIC packaging matching the original 74LCX646WMX footprint. The SN74LVC646APW uses 24-TSSOP packaging with smaller dimensions (0.173", 4.40mm width), requiring PCB layout modification but offering reduced board space consumption.

Q: Are the supply voltage ranges compatible?

A: Yes. Both substitute parts operate across 1.65V to 3.6V, which fully encompasses the original 2V to 3.6V specification. This expanded range provides additional design flexibility without compromising compatibility.

Q: What is the significance of the obsolete product status for the 74LCX646WMX?

A: Obsolete status indicates the component is no longer manufactured by onsemi. Substitution with active-status alternatives (SN74LVC646ADW or SN74LVC646APW) ensures continued availability for production and future design iterations.

Q: Do the substitute parts meet the same compliance requirements?

A: Both Texas Instruments substitutes are RoHS3 compliant with MSL 1 (Unlimited) moisture sensitivity rating, matching the regulatory and environmental specifications of the original component.

Q: Are there any electrical performance differences between the three parts?

A: No. All three components maintain identical output current specifications (24mA high and low), operating temperature range (-40°C to 85°C), and logic function (non-inverting transceiver with 8-bit, 3-state output).