SN74LS21D AND Gate IC Equivalent & Substitute Parts

Part Overview

The SN74LS21D is a 2-channel AND gate logic IC manufactured by Texas Instruments in 14-SOIC surface mount packaging. This component is classified as discontinued at DiGi Electronics, making substitute parts necessary for ongoing production and maintenance applications. The SN74LS21D operates within the 74LS logic family and provides dual 4-input AND gate functionality for digital logic circuit design.

Substiute Parts

SN74LS21D

Texas InstrumentsIn Stock: 2382SN74LS21D Datasheet

Current PartRFQ

SN74LS21DR

Texas InstrumentsIn Stock: 2305SN74LS21DR Datasheet

DirectRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitution of the SN74LS21D is determined by strict equivalence across the following critical parameters:

• Logic function: AND Gate with 2 channels and 4 inputs per channel
• Electrical specifications: Supply voltage 4.75V ~ 5.25V, output current 400µA/8mA, input logic levels 0.8V/2V, propagation delay 20ns @ 5V with 15pF load
• Package type: 14-SOIC surface mount form factor
• Thermal range: 0°C ~ 70°C operating temperature
• Compliance: ROHS3 compliant, MSL Level 1

The SN74LS21DR qualifies as a direct substitute based on identical electrical characteristics, logic configuration, and package specifications. The primary distinction is packaging format and product status.

Parameter Comparison

Engineering Selection Recommendations

The SN74LS21DR is the direct equivalent substitute for the SN74LS21D. Both parts share identical electrical and functional specifications with full parameter alignment across logic operation, voltage supply, output current, input thresholds, and propagation delay characteristics.

The SN74LS21DR maintains active product status with Texas Instruments, ensuring continued availability and supply chain reliability. Both components meet ROHS3 compliance and MSL Level 1 requirements, supporting equivalent environmental and regulatory standards.

The distinction between these parts is packaging format: the SN74LS21D is supplied in tube packaging, while the SN74LS21DR is supplied in Tape & Reel format. This difference does not affect electrical performance or functional compatibility in circuit applications.

Frequently Asked Questions (FAQ)

Q: Can the SN74LS21DR directly replace the SN74LS21D in existing designs?

A: Yes. The SN74LS21DR is electrically and functionally identical to the SN74LS21D. All electrical parameters, logic specifications, and operating characteristics are equivalent. The 14-SOIC package dimensions are identical, supporting direct PCB footprint compatibility.

Q: What is the difference between tube and Tape & Reel packaging?

A: Tube packaging supplies components in plastic tubes for manual handling and smaller quantity orders. Tape & Reel packaging supplies components on continuous tape for automated assembly equipment. Both formats contain identical components with no electrical or performance differences.

Q: Are there any compliance or certification differences between these parts?

A: No. Both the SN74LS21D and SN74LS21DR carry identical ROHS3 compliance and MSL Level 1 ratings. Regulatory and environmental certifications are equivalent.

Q: Why is the SN74LS21D listed as discontinued?

A: The SN74LS21D is discontinued at DiGi Electronics, indicating it is no longer actively stocked by this distributor. The SN74LS21DR remains in active production status, making it the recommended selection for new orders and ongoing supply requirements.

Q: Do these parts require different handling or storage procedures?

A: No. Both parts share identical Moisture Sensitivity Level (MSL) ratings of Level 1 (Unlimited), indicating no special moisture control requirements during storage or handling.