SN74LS645-1DW Equivalent & Substitute Parts

Part Overview

The SN74LS645-1DW is a non-inverting transceiver logic integrated circuit manufactured by Texas Instruments. This component functions as a 1-element, 8-bit transceiver with 3-state output capability, designed for 5V logic applications. The part is classified as Last Time Buy, indicating discontinued production status. Identifying equivalent substitute parts is necessary to ensure continued component availability for maintenance, repair, and new production runs where legacy compatibility is required.

Substiute Parts

SN74LS645-1DW

Texas InstrumentsIn Stock: 943SN74LS645-1DW Datasheet

Current PartRFQ

SN74LS645-1DWR

Texas InstrumentsIn Stock: 2453SN74LS645-1DWR Datasheet

MFR RecommendedRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitution of the SN74LS645-1DW is determined by strict equivalence across the following critical parameters:

• Logic Type: Transceiver, Non-Inverting
• Number of Elements: 1
• Number of Bits per Element: 8
• Output Type: 3-State
• Current Specifications: 15mA (Output High), 48mA (Output Low)
• Voltage Supply Range: 4.75V ~ 5.25V
• Operating Temperature Range: 0°C ~ 70°C
• Package / Case: 20-SOIC (0.295", 7.50mm Width)
• Mounting Type: Surface Mount

The primary substitute identified is the SN74LS645-1DWR, which maintains identical electrical and mechanical specifications. The distinction between these parts is limited to packaging format: the original part is supplied in Tube packaging, while the substitute is supplied in Tape & Reel (TR) format. Both parts share the same base product number (74LS645) and are manufactured by Texas Instruments.

Parameter Comparison

Engineering Selection Recommendations

The SN74LS645-1DWR serves as the direct functional equivalent to the SN74LS645-1DW. Both parts are manufactured by Texas Instruments and maintain identical electrical characteristics and physical package specifications. The SN74LS645-1DWR holds Active product status, ensuring continued availability and support, whereas the original part is designated Last Time Buy.

Selection between these parts should be based on packaging requirements and supply chain considerations. The Tube packaging format of the original part is suitable for lower-volume applications and manual assembly processes. The Tape & Reel format of the substitute part is optimized for high-volume automated assembly operations. Both parts satisfy ROHS3 compliance and REACH requirements, making them suitable for applications with environmental regulatory constraints.

Frequently Asked Questions (FAQ)

Q: Can the SN74LS645-1DWR be used as a direct replacement for the SN74LS645-1DW?

A: Yes. Both parts are electrically and mechanically identical. The only difference is the packaging format: Tube versus Tape & Reel. Functional performance, pin configuration, electrical specifications, and thermal characteristics are equivalent.

Q: What is the difference between Tube and Tape & Reel packaging?

A: Tube packaging supplies individual components in a plastic tube, suitable for small quantities and manual handling. Tape & Reel packaging supplies components on a continuous carrier tape wound on a reel, optimized for automated pick-and-place assembly equipment. The actual component specifications remain unchanged.

Q: Are there any compatibility concerns when substituting the SN74LS645-1DWR for the SN74LS645-1DW?

A: No compatibility concerns exist. Both parts share identical pin assignments, electrical performance, and package dimensions. Substitution is valid for all applications where the original part was specified.

Q: Why is the SN74LS645-1DW marked as Last Time Buy?

A: Last Time Buy status indicates that Texas Instruments has discontinued production of this part number. The SN74LS645-1DWR, with Active status, represents the current production equivalent and should be used for new designs and ongoing procurement.

Q: What are the key electrical parameters that define substitution compatibility?

A: Substitution compatibility is determined by: Logic Type (Transceiver, Non-Inverting), Number of Elements (1), Bits per Element (8), Output Type (3-State), Output Current specifications (15mA High, 48mA Low), Supply Voltage range (4.75V ~ 5.25V), Operating Temperature range (0°C ~ 70°C), and Package type (20-SOIC).

Q: Are both parts RoHS and REACH compliant?

A: Yes. Both the SN74LS645-1DW and SN74LS645-1DWR are ROHS3 Compliant and REACH Unaffected, meeting environmental and regulatory requirements for electronic component manufacturing and use.