SN74LS540DW Equivalent & Substitute Parts

Part Overview

The SN74LS540DW is a Buffer, Inverting logic IC manufactured by Texas Instruments, designed for 5.25V operation with 1 element and 8 bits per element configuration. This component features 3-State output capability in a 20-SOIC surface mount package. The product is currently discontinued at DiGi Electronics, making identification of equivalent substitute parts essential for ongoing design support and procurement planning.

Substiute Parts

SN74LS540DW

Texas InstrumentsIn Stock: 2151SN74LS540DW Datasheet

Current PartRFQ

SN74LS540DWR

Texas InstrumentsIn Stock: 3208SN74LS540DWR Datasheet

DirectRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitute parts for the SN74LS540DW are identified based on strict electrical and mechanical parameter matching. The following criteria determine substitution eligibility:

Critical Matching Parameters:

• Logic Type: Buffer, Inverting
• Number of Elements: 1
• Number of Bits per Element: 8
• Output Type: 3-State
• Current - Output High, Low: 15mA, 24mA
• Voltage - Supply: 4.75V ~ 5.25V
• Operating Temperature: 0°C ~ 70°C (TA)
• Package / Case: 20-SOIC (0.295", 7.50mm Width)
• Base Product Number: 74LS540

The SN74LS540DWR qualifies as a direct substitute, sharing identical electrical specifications and package configuration. The primary distinction is packaging format: the original part is supplied in Tube packaging, while the substitute is supplied in Tape & Reel (TR) format. Both parts maintain the same functional performance and physical footprint for PCB assembly.

Parameter Comparison

Engineering Selection Recommendations

The SN74LS540DWR is a direct functional equivalent to the SN74LS540DW. Both parts are manufactured by Texas Instruments and maintain identical electrical performance specifications, output characteristics, and thermal operating ranges. The SN74LS540DWR holds Active product status, ensuring continued availability and supply chain support.

Selection between these parts depends on procurement and assembly requirements. The Tube packaging format of the original part suits lower-volume or manual assembly operations, while the Tape & Reel format of the substitute supports automated pick-and-place assembly processes. Both parts meet ROHS3 compliance and REACH requirements, with MSL rating of 1 indicating unlimited moisture sensitivity protection.

Frequently Asked Questions (FAQ)

Q: Can the SN74LS540DWR be used as a direct replacement for the SN74LS540DW?

A: Yes. Both parts share identical electrical specifications, output characteristics, supply voltage range, operating temperature range, and 20-SOIC package dimensions. The only difference is the packaging format: Tube versus Tape & Reel.

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

A: Tube packaging is used for manual handling and lower-volume assembly. Tape & Reel packaging is designed for automated pick-and-place assembly equipment. The components themselves are electrically and mechanically identical.

Q: Are there any compliance differences between these parts?

A: No. Both parts maintain ROHS3 compliance, REACH Unaffected status, and MSL rating of 1 (Unlimited). Regulatory and environmental certifications are identical.

Q: Why is the original SN74LS540DW discontinued?

A: Product discontinuation at DiGi Electronics does not affect the technical performance or specifications of existing inventory. The SN74LS540DWR remains in Active status and provides equivalent functionality for new designs and replacements.

Q: Will the SN74LS540DWR work in existing PCB designs for the SN74LS540DW?

A: Yes. The 20-SOIC package footprint is identical, and all electrical parameters match. No PCB redesign is required.