DM74ALS540ASJ Equivalent & Substitute Parts

Part Overview

The DM74ALS540ASJ is an inverting buffer logic IC manufactured by onsemi, featuring 1 element with 8 bits per element and 3-state output capability. This component operates within a 4.5V to 5.5V supply voltage range and is rated for 0°C to 70°C operating temperature. The part is classified as obsolete, making identification of equivalent and substitute components essential for ongoing system support and procurement planning.

Substiute Parts

DM74ALS540ASJ

onsemiIn Stock: 1117DM74ALS540ASJ Datasheet

Current PartRFQ

SN74ALS540NSR

Texas InstrumentsIn Stock: 2229SN74ALS540NSR Datasheet

DirectRFQ

SN74ALS540-1NSR

Texas InstrumentsIn Stock: 6308SN74ALS540-1NSR Datasheet

SimilarRFQ

SN74ALS540DW

Texas InstrumentsIn Stock: 4017SN74ALS540DW Datasheet

SimilarRFQ

SN74ALS540DWR

Texas InstrumentsIn Stock: 3158SN74ALS540DWR Datasheet

SimilarRFQ

SN74ALS540NS

Texas InstrumentsIn Stock: 1077SN74ALS540NS Datasheet

Parametric EquivalentRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitute parts for the DM74ALS540ASJ are classified based on electrical and mechanical compatibility within the 74ALS logic family. The substitution logic is determined by the following critical parameters:

Electrical Compatibility Criteria:

• Logic Type: Buffer, Inverting (must match)
• Number of Elements: 1 (must match)
• Number of Bits per Element: 8 (must match)
• Output Type: 3-State (must match)
• Voltage - Supply: 4.5V ~ 5.5V (must match)
• Operating Temperature: 0°C ~ 70°C (TA) (must match)
• Current - Output High, Low: 15mA, 24mA (must match or be within acceptable range)

Mechanical Compatibility Criteria:

• Mounting Type: Surface Mount (must match)
• Package / Case: 20-SOIC or 20-SO variants (compatible footprints)

All substitute parts listed maintain identical electrical specifications and are manufactured by Texas Instruments, an active supplier within the 74ALS series. Substitutes are grouped by packaging configuration and product status.

Parameter Comparison

Engineering Selection Recommendations

Direct Substitutes (Identical Electrical and Mechanical Parameters):

SN74ALS540NSR, SN74ALS540NS, and SN74ALS540-1NSR are direct electrical equivalents with matching 20-SOIC (0.209", 5.30mm Width) packaging. SN74ALS540NSR and SN74ALS540DWR are classified as active products, ensuring long-term availability and supply chain stability. These parts are ROHS3 compliant and carry MSL 1 rating identical to the original component.

Package Variant Substitutes:

SN74ALS540DW and SN74ALS540DWR feature a wider 20-SOIC (0.295", 7.50mm Width) package variant. While electrically identical, these parts require PCB layout verification to confirm mechanical compatibility with existing footprints designed for the narrower 0.209" width package.

Output Current Consideration:

SN74ALS540-1NSR specifies output low current of 48mA compared to the standard 24mA. This higher current capability is a superset of the original specification and does not restrict substitution in applications requiring standard current levels.

Product Status Impact:

Texas Instruments SN74ALS540NSR and SN74ALS540DWR maintain active product status, providing the most reliable long-term procurement path. SN74ALS540DW and SN74ALS540NS are designated Last Time Buy, indicating limited future availability.

Frequently Asked Questions (FAQ)

Q: Can SN74ALS540DW be used as a direct replacement for DM74ALS540ASJ?

A: SN74ALS540DW is electrically equivalent but features a different package width (0.295" versus 0.209"). PCB footprint compatibility must be verified before substitution. If the original design accommodates the wider package, substitution is valid.

Q: What is the difference between SN74ALS540NSR and SN74ALS540-1NSR?

A: Both parts are electrically compatible with identical logic function and supply voltage. SN74ALS540-1NSR specifies higher output low current (48mA versus 24mA). For applications requiring standard 24mA output, either part is suitable. The "-1" designation indicates the enhanced current variant.

Q: Are all substitute parts ROHS3 compliant?

A: Yes. All Texas Instruments substitute parts listed (SN74ALS540NSR, SN74ALS540-1NSR, SN74ALS540DW, SN74ALS540DWR, SN74ALS540NS) are ROHS3 compliant. The original onsemi DM74ALS540ASJ RoHS status is not specified in available documentation.

Q: Which substitute offers the best long-term availability?

A: SN74ALS540NSR and SN74ALS540DWR maintain active product status from Texas Instruments, ensuring continued manufacturing and supply. These are preferred for new designs and long-term production requirements.

Q: Can packaging be mixed within a single assembly?

A: Packaging variants (20-SOIC 0.209" width versus 0.295" width) require separate PCB footprints. Mixed packaging within a single assembly is possible only if the PCB design accommodates both footprint geometries.

Q: What is the significance of MSL 1 rating?

A: MSL 1 (Unlimited) indicates unlimited shelf life without moisture bake-out requirements. All parts in this comparison carry MSL 1 rating, eliminating moisture sensitivity as a substitution constraint.