DM74AS21M Equivalent & Substitute Parts

Part Overview

The DM74AS21M is a 2-channel AND gate logic IC manufactured by onsemi in a 14-SOIC surface mount package. This component implements dual 4-input AND gate functions with TTL-compatible logic levels and is currently classified as obsolete. Due to its obsolete status, identifying functionally equivalent active alternatives is essential for design continuity and procurement planning.

Substiute Parts

DM74AS21M

onsemiIn Stock: 1559DM74AS21M Datasheet

Current PartRFQ

SN74AS21NSR

Texas InstrumentsIn Stock: 1194SN74AS21NSR Datasheet

SimilarRFQ

SN74AS21D

Texas InstrumentsIn Stock: 1428SN74AS21D Datasheet

Parametric EquivalentRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitute parts for the DM74AS21M are qualified based on strict electrical and mechanical parameter matching within the 74AS logic family. The following criteria determine substitution eligibility:

• Logic type: AND Gate with 2 channels and 4 inputs per channel
• Electrical specifications: Supply voltage 4.5V ~ 5.5V, output current 2mA/20mA, input logic levels 0.8V (low) and 2V (high), propagation delay 6ns @ 5V with 50pF load
• Operating temperature range: 0°C ~ 70°C
• Mounting type: Surface Mount
• Package compatibility: 14-SOIC form factor

Both identified substitutes meet all electrical parameters identically and maintain the same base product number (74AS21), ensuring functional equivalence.

Parameter Comparison

Engineering Selection Recommendations

Both SN74AS21NSR and SN74AS21D are active product alternatives manufactured by Texas Instruments with identical electrical and functional specifications to the obsolete DM74AS21M. Both substitutes are ROHS3 compliant, providing regulatory advantage over the original component.

SN74AS21NSR is supplied in Tape & Reel packaging with a 14-SO package variant (0.209", 5.30mm width). SN74AS21D is supplied in Tube packaging with the standard 14-SOIC package (0.154", 3.90mm width) matching the original DM74AS21M footprint exactly.

For direct board-level replacement without layout modification, SN74AS21D is the preferred selection due to identical package dimensions. SN74AS21NSR is suitable for high-volume automated assembly applications where tape and reel packaging is standard.

Frequently Asked Questions (FAQ)

Q: Can SN74AS21NSR and SN74AS21D be used interchangeably with DM74AS21M?

A: Both parts are electrically equivalent and functionally identical. SN74AS21D maintains the same 14-SOIC package footprint as DM74AS21M. SN74AS21NSR uses a 14-SO package variant with different physical dimensions (0.209" vs 0.154" width), requiring PCB layout verification before substitution.

Q: What is the difference between the two Texas Instruments substitutes?

A: The primary difference is packaging format and supplier delivery method. SN74AS21NSR is supplied in Tape & Reel format suitable for automated pick-and-place assembly. SN74AS21D is supplied in Tube format. Both are electrically identical with the same logic specifications and operating parameters.

Q: Are there compliance or regulatory differences between the original and substitutes?

A: SN74AS21NSR and SN74AS21D are both ROHS3 compliant, providing environmental compliance advantage. All three parts share identical REACH status (REACH Unaffected) and ECCN classification (EAR99).

Q: Does package selection affect circuit performance?

A: No. All three parts operate identically within the specified electrical parameters. Package selection is determined by PCB footprint requirements and assembly process compatibility, not performance characteristics.

Q: What inventory status should influence procurement decisions?

A: SN74AS21D has 1417 pieces in stock, SN74AS21NSR has 1092 pieces in stock, and DM74AS21M has 1500 pieces in stock. For new designs, active product alternatives (both TI parts) are recommended to ensure long-term supply continuity.