SN74LS640DW Equivalent & Substitute Parts

Part Overview

The SN74LS640DW is a Logic Transceiver, Inverting integrated circuit manufactured by Texas Instruments. This component functions as a 1 Element, 8 Bit per Element transceiver with 3-State output capability, designed for 5.25V operation in 20-SOIC surface mount packaging. The SN74LS640DW carries a Last Time Buy product status, indicating discontinued production. Identifying equivalent substitute parts is necessary to maintain design continuity and ensure component availability for new production runs and field replacements.

Substiute Parts

SN74LS640DW

Texas InstrumentsIn Stock: 3328SN74LS640DW Datasheet

Current PartRFQ

SN74LS640DWR

Texas InstrumentsIn Stock: 3497SN74LS640DWR Datasheet

MFR RecommendedRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitute parts for the SN74LS640DW are determined by strict equivalence across the following critical parameters:

• Logic Type: Transceiver, 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)
• Mounting Type: Surface Mount
• Base Product Number: 74LS640

The SN74LS640DWR qualifies as a direct substitute based on identical electrical specifications and mechanical compatibility. The primary distinction is packaging format: the SN74LS640DWR is supplied in Tape & Reel (TR) format, whereas the SN74LS640DW is supplied in standard packaging. Both components share the same 20-SOIC footprint and electrical performance characteristics.

Parameter Comparison

Engineering Selection Recommendations

The SN74LS640DWR is the direct substitute for the SN74LS640DW. Both components are ROHS3 compliant and carry MSL Level 1 rating, indicating equivalent environmental and regulatory compliance. The SN74LS640DWR maintains Active product status, ensuring continued availability and manufacturing support from Texas Instruments, whereas the SN74LS640DW is designated Last Time Buy. For new designs and production requirements, the SN74LS640DWR is the appropriate selection. The packaging format difference (Tape & Reel versus standard packaging) does not affect electrical or mechanical compatibility; selection between these variants depends on assembly process requirements and volume considerations.

Frequently Asked Questions (FAQ)

Q: Can the SN74LS640DWR be used as a direct replacement for the SN74LS640DW in existing designs?

A: Yes. Both components share identical electrical specifications, output characteristics, supply voltage range, operating temperature range, and 20-SOIC footprint. No circuit modifications are required.

Q: What is the difference between SN74LS640DW and SN74LS640DWR?

A: The primary difference is packaging format. The SN74LS640DW uses standard packaging, while the SN74LS640DWR is supplied in Tape & Reel (TR) format. Electrical performance and mechanical compatibility are identical.

Q: Why is the SN74LS640DW marked as Last Time Buy?

A: Last Time Buy status indicates that Texas Instruments has discontinued production of this component. The SN74LS640DWR, with Active status, represents the current manufacturing option.

Q: Are there any compliance differences between these parts?

A: No. Both components are ROHS3 compliant, carry identical Moisture Sensitivity Level (MSL) ratings, and meet the same regulatory requirements.

Q: What assembly considerations apply when switching from SN74LS640DW to SN74LS640DWR?

A: The Tape & Reel format of the SN74LS640DWR is optimized for automated assembly processes. Standard packaging of the SN74LS640DW may be preferred for manual or low-volume assembly. Both formats are compatible with standard 20-SOIC placement equipment.