DM74ALS540ASJX Equivalent & Substitute Parts

Part Overview

The DM74ALS540ASJX is an inverting buffer logic integrated circuit manufactured by onsemi, designed for 5.5V operation with 3-state output capability. This component belongs to the 74ALS logic family and provides 1 element with 8 bits per element configuration in a 20-SOP package. The part is currently classified as obsolete, making identification of functionally equivalent alternatives essential for ongoing system support and new design implementations.

Substiute Parts

DM74ALS540ASJX

onsemiIn Stock: 1160DM74ALS540ASJX Datasheet

Current PartRFQ

SN74ALS540-1NSR

Texas InstrumentsIn Stock: 6308SN74ALS540-1NSR Datasheet

SimilarRFQ

SN74ALS540DW

Texas InstrumentsIn Stock: 4017SN74ALS540DW Datasheet

SimilarRFQ

SN74ALS540DWR

Texas InstrumentsIn Stock: 3158SN74ALS540DWR Datasheet

SimilarRFQ

SN74ALS540NSR

Texas InstrumentsIn Stock: 2229SN74ALS540NSR Datasheet

Parametric EquivalentRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitution for the DM74ALS540ASJX is determined by strict equivalence across the following critical parameters:

• Logic Type: Buffer, Inverting (1 element, 8 bits per element)
• Output Type: 3-State
• Voltage Supply Range: 4.5V ~ 5.5V
• Operating Temperature Range: 0°C ~ 70°C (TA)
• Output Current Specifications: 15mA (High), 24mA (Low)
• Mounting Type: Surface Mount
• Base Product Number: 74ALS540
• Moisture Sensitivity Level: 1 (Unlimited)

Substitute parts are grouped into two categories based on package configuration and product status:

Group 1: Direct Package Equivalents (20-SOIC, 0.295" Width)

• SN74ALS540DW (Tube packaging, Last Time Buy status)
• SN74ALS540DWR (Tape & Reel packaging, Active status)

Group 2: Alternate Package Configuration (20-SOIC, 0.209" Width)

• SN74ALS540-1NSR (Tape & Reel packaging, Active status)
• SN74ALS540NSR (Active status)

All substitute parts maintain identical logic functionality, electrical performance, and thermal operating range as the original DM74ALS540ASJX.

Parameter Comparison

Engineering Selection Recommendations

For New Designs and Long-Term Availability: SN74ALS540DWR and SN74ALS540-1NSR are the preferred selections. Both parts carry Active product status from Texas Instruments, ensuring continued availability and supply chain stability. SN74ALS540DWR is supplied in Tape & Reel packaging with a 20-SOIC (0.295", 7.50mm Width) configuration, while SN74ALS540-1NSR offers the same 20-SOIC (0.209", 5.30mm Width) package width as the original DM74ALS540ASJX. Both are ROHS3 compliant.

For Existing Inventory Management: SN74ALS540NSR provides parametric equivalence with Active status and matches the original package width of 0.209". This part is suitable for applications where existing PCB layouts require the narrower package configuration.

For Legacy System Support: SN74ALS540DW remains available with Last Time Buy status. This part maintains identical electrical specifications and output current ratings (15mA, 24mA) as the original DM74ALS540ASJX, making it suitable for direct replacement in existing systems. However, procurement should prioritize Active-status alternatives for future orders.

Package Consideration: SN74ALS540-1NSR exhibits higher output low current (48mA versus 24mA). While this represents enhanced drive capability, applications with current-sensitive designs should verify compatibility with existing load specifications.

Frequently Asked Questions (FAQ)

Q: Can SN74ALS540-1NSR be used as a direct replacement for DM74ALS540ASJX? A: SN74ALS540-1NSR is functionally equivalent in logic operation, voltage supply range, operating temperature, and package width. However, it specifies 48mA output low current compared to the original 24mA specification. Applications must confirm that higher output current does not create design conflicts.

Q: What is the difference between the 20-SOIC (0.209") and 20-SOIC (0.295") packages? A: The primary difference is package width. The 0.209" width variant (used in DM74ALS540ASJX, SN74ALS540-1NSR, and SN74ALS540NSR) is narrower than the 0.295" width variant (used in SN74ALS540DW and SN74ALS540DWR). PCB layout and footprint compatibility must be verified before substitution.

Q: Why is the DM74ALS540ASJX classified as obsolete? A: Obsolete status indicates the part is no longer manufactured by onsemi. Texas Instruments continues to produce functionally equivalent 74ALS540 variants, making substitution necessary for ongoing system support.

Q: Are all substitute parts RoHS3 compliant? A: Yes. All Texas Instruments substitute parts (SN74ALS540-1NSR, SN74ALS540DW, SN74ALS540DWR, and SN74ALS540NSR) are specified as ROHS3 compliant. The original DM74ALS540ASJX does not specify RoHS status.

Q: Which substitute part offers the best long-term availability? A: SN74ALS540DWR and SN74ALS540-1NSR both carry Active product status from Texas Instruments, indicating ongoing production and supply commitment. SN74ALS540DW is designated Last Time Buy, indicating limited future availability.

Q: Can I mix substitute parts within the same design? A: All substitute parts maintain identical logic functionality, voltage supply range, and operating temperature specifications. However, package width differences (0.209" versus 0.295") require separate PCB footprints. Output current specifications must be verified for each application context.