DM74ALS21AMX Equivalent & Substitute Parts

Part Overview

The DM74ALS21AMX is a 2-channel AND gate logic IC manufactured by onsemi, housed in a 14-SOIC package. This component implements dual 4-input AND gate functions with TTL-compatible logic levels and is classified as obsolete. Due to its obsolete status, identifying functionally equivalent substitute parts from active manufacturers is essential for design continuity and procurement reliability.

Substiute Parts

DM74ALS21AMX

onsemiIn Stock: 3119DM74ALS21AMX Datasheet

Current PartRFQ

SN74ALS21AD

Texas InstrumentsIn Stock: 1457SN74ALS21AD Datasheet

DirectRFQ

SN74ALS21ANSR

Texas InstrumentsIn Stock: 3336SN74ALS21ANSR Datasheet

SimilarRFQ

SN74ALS21ADR

Texas InstrumentsIn Stock: 3710SN74ALS21ADR Datasheet

Parametric EquivalentRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitute parts for the DM74ALS21AMX are classified based on electrical and mechanical compatibility with the following critical parameters:

Electrical Compatibility Criteria:

• Logic Type: AND Gate (2 channels, 4 inputs per channel)
• Supply Voltage: 4.5V ~ 5.5V
• Output Current: 400µA (high), 8mA (low)
• Input Logic Levels: 0.8V (low), 2V (high)
• Propagation Delay: 15ns @ 5V, 50pF
• Operating Temperature: 0°C ~ 70°C
• Series: 74ALS

Mechanical Compatibility Criteria:

• Mounting Type: Surface Mount
• Package Family: 14-SOIC or 14-SO

The substitute parts are grouped as follows:

Direct Manufacturer Equivalent (SN74ALS21AD): Identical electrical specifications and primary package format (14-SOIC, 0.154" width). Differs only in product status (Last Time Buy) and packaging method (Tube vs. original specification).

Similar Manufacturer Equivalent (SN74ALS21ANSR): Identical electrical specifications with minor package variation (14-SO, 0.209" width instead of 0.154"). Packaged in Tape & Reel format. Active product status.

Parametric Equivalent (SN74ALS21ADR): Identical electrical specifications and primary package format (14-SOIC, 0.154" width). Packaged in Tape & Reel format. Active product status.

Parameter Comparison

Engineering Selection Recommendations

For New Designs and Long-Term Availability: SN74ALS21ADR (Texas Instruments) is the preferred substitute. This part maintains identical electrical specifications and primary package dimensions (14-SOIC, 0.154" width) while offering active product status, ROHS3 compliance, and Tape & Reel packaging suitable for automated assembly processes.

For Direct Pin-Compatible Replacement with Minimal PCB Modification: SN74ALS21AD (Texas Instruments) provides direct electrical and mechanical equivalence to the DM74ALS21AMX. However, its Last Time Buy status indicates limited future availability. This option is suitable for legacy system repairs or short-term production runs.

For Applications with Package Tolerance: SN74ALS21ANSR (Texas Instruments) offers active product status and full electrical compatibility. The package width variation (0.209" vs. 0.154") requires PCB footprint verification but does not affect electrical performance. This part is suitable for designs where package width tolerance is acceptable.

All three Texas Instruments substitutes maintain REACH Unaffected status and MSL 1 rating, ensuring compliance with environmental and moisture sensitivity requirements.

Frequently Asked Questions (FAQ)

Q: Can SN74ALS21ANSR be used as a direct replacement for DM74ALS21AMX on existing PCBs?

A: SN74ALS21ANSR is electrically equivalent but has a different package width (0.209" vs. 0.154"). Pin pitch and lead count remain identical. PCB footprint compatibility must be verified before substitution. If the PCB footprint accommodates the wider package, direct substitution is possible.

Q: What is the difference between SN74ALS21AD and SN74ALS21ADR?

A: Both parts are electrically and mechanically identical with matching package specifications (14-SOIC, 0.154" width). The primary difference is packaging method: SN74ALS21AD is supplied in Tube format, while SN74ALS21ADR is supplied in Tape & Reel format. SN74ALS21ADR is preferred for automated assembly processes.

Q: Why is the DM74ALS21AMX marked as obsolete?

A: The DM74ALS21AMX is an onsemi product with obsolete status. Texas Instruments maintains active production of functionally equivalent 74ALS21 variants, making TI substitutes the recommended path for continued supply.

Q: Are all substitute parts ROHS3 compliant?

A: Yes. All three Texas Instruments substitutes (SN74ALS21AD, SN74ALS21ANSR, SN74ALS21ADR) are ROHS3 compliant. The original DM74ALS21AMX RoHS status is not specified in available documentation.

Q: Do the substitute parts maintain the same operating temperature range?

A: Yes. All substitute parts operate within the identical temperature range of 0°C ~ 70°C, matching the DM74ALS21AMX specification.

Q: What is the significance of MSL 1 (Unlimited) rating?

A: MSL 1 indicates unlimited shelf life without moisture bake-out requirements. All parts in this comparison carry MSL 1 rating, meaning standard storage conditions are sufficient without special moisture control procedures.