DM74AS21MX Equivalent & Substitute Parts

Part Overview

The DM74AS21MX is a 2-channel AND gate logic IC in 14-SOIC surface mount packaging, manufactured by onsemi. 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

DM74AS21MX

onsemiIn Stock: 2879DM74AS21MX Datasheet

Current PartRFQ

SN74AS21D

Texas InstrumentsIn Stock: 1428SN74AS21D Datasheet

DirectRFQ

SN74AS21NSR

Texas InstrumentsIn Stock: 1194SN74AS21NSR Datasheet

SimilarRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitute parts for the DM74AS21MX are qualified based on strict electrical and mechanical parameter matching within the 74AS logic family. The following criteria determine substitution validity:

Electrical Parameters (Must Match):

• Logic Type: AND Gate
• Number of Circuits: 2
• Number of Inputs: 4
• Voltage - Supply: 4.5V ~ 5.5V
• Current - Output High, Low: 2mA, 20mA
• Input Logic Level - Low: 0.8V
• Input Logic Level - High: 2V
• Max Propagation Delay @ V, Max CL: 6ns @ 5V, 50pF
• Operating Temperature: 0°C ~ 70°C
• Series: 74AS

Mechanical Parameters (Must Match or Be Compatible):

• Mounting Type: Surface Mount
• Package / Case: 14-SOIC or equivalent footprint

Two substitute parts meet these criteria: SN74AS21D (direct equivalent) and SN74AS21NSR (similar equivalent with package variation).

Parameter Comparison

Engineering Selection Recommendations

SN74AS21D (Direct Equivalent): This part is the primary substitute for the DM74AS21MX. It matches all electrical parameters identically and maintains the same 14-SOIC (0.154", 3.90mm Width) package footprint. The SN74AS21D is manufactured by Texas Instruments with active product status and ROHS3 compliance, providing long-term availability and regulatory alignment.

SN74AS21NSR (Similar Equivalent): This part matches all electrical parameters and maintains 74AS series compatibility. The primary distinction is the package width specification: 14-SOIC (0.209", 5.30mm Width) versus the original 0.154" width. This package variation may affect PCB layout compatibility depending on board design constraints. The SN74AS21NSR is supplied in Tape & Reel format and carries ROHS3 compliance and active product status.

Frequently Asked Questions (FAQ)

Q: Can SN74AS21D be used as a direct replacement for DM74AS21MX? A: Yes. The SN74AS21D matches all electrical specifications and maintains identical package dimensions (14-SOIC, 0.154" width), enabling direct substitution without circuit or layout modifications.

Q: What is the difference between SN74AS21D and SN74AS21NSR? A: Both parts are electrically identical and belong to the 74AS series. The primary difference is package width: SN74AS21D uses 0.154" width while SN74AS21NSR uses 0.209" width. This affects PCB footprint compatibility. SN74AS21NSR is supplied in Tape & Reel packaging, while SN74AS21D is supplied in Tube packaging.

Q: Are the substitute parts RoHS compliant? A: Yes. Both SN74AS21D and SN74AS21NSR are ROHS3 compliant, meeting current environmental and regulatory requirements.

Q: Will the substitute parts work in the same operating temperature range? A: Yes. All substitute parts operate within the same temperature range of 0°C to 70°C as the original DM74AS21MX.

Q: What should I consider when selecting between the two substitutes? A: Selection depends on PCB layout requirements and packaging format needs. If your board design accommodates the 0.209" package width, either part is suitable. If your layout requires the original 0.154" width, SN74AS21D is the appropriate choice. Consider packaging format availability: SN74AS21D in Tube or SN74AS21NSR in Tape & Reel.