SN74HC21DG4 Equivalent & Substitute Parts

Part Overview

The SN74HC21DG4 is a dual 4-input AND gate logic IC manufactured by Texas Instruments, housed in a 14-SOIC surface mount package. This component is classified as discontinued at DiGi Electronics, creating a need for equivalent alternatives that maintain functional and electrical compatibility. The 74HC21 series provides two independent AND gate circuits with 4 inputs each, suitable for digital logic applications requiring AND gate functionality in compact form factors.

Substiute Parts

SN74HC21DG4

Texas InstrumentsIn Stock: 765SN74HC21DG4 Datasheet

Current PartRFQ

SN74HC21DR

Texas InstrumentsIn Stock: 3655SN74HC21DR Datasheet

DirectRFQ

SN74HC21D

Texas InstrumentsIn Stock: 10684SN74HC21D Datasheet

MFR RecommendedRFQ

74HC21D,653

Nexperia USA Inc.In Stock: 2026674HC21D,653 Datasheet

UpgradeRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitution for the SN74HC21DG4 is determined by strict equivalence across the following electrical and mechanical parameters:

Critical Substitution Parameters:

• Logic Type: AND Gate (2 channels, 4 inputs per channel)
• Voltage Supply Range: 2V ~ 6V
• Max Propagation Delay: 19ns @ 6V, 50pF
• Current Specifications: Quiescent 2µA max; Output 5.2mA high/low
• Input Logic Levels: Low 0.5V ~ 1.8V; High 1.5V ~ 4.2V
• Package: 14-SOIC surface mount
• RoHS3 Compliance

The substitute parts listed maintain identical electrical performance and functional specifications. Differences in product status, packaging format (tape & reel vs. cut tape vs. tube), and manufacturer do not affect circuit-level compatibility when these core parameters align.

Parameter Comparison

Engineering Selection Recommendations

SN74HC21DR (Direct Substitute - Recommended Primary Choice)

The SN74HC21DR is the direct equivalent manufactured by Texas Instruments with active product status. All electrical parameters, timing specifications, and package dimensions are identical to the SN74HC21DG4. This part is available in cut tape and Digi-Reel packaging formats with 3590 units in stock, providing immediate availability for production requirements.

74HC21D,653 (Extended Temperature Alternative)

The 74HC21D,653 manufactured by Nexperia USA Inc. provides identical electrical and functional specifications with an extended operating temperature range of -40°C to 125°C compared to the standard -40°C to 85°C. This part maintains active product status and is available in tape & reel packaging with 20186 units in stock. Selection of this part is appropriate for applications requiring enhanced thermal performance or operation in elevated temperature environments.

SN74HC21D (Secondary Option)

The SN74HC21D is the manufacturer-recommended alternative from Texas Instruments, functionally equivalent across all critical parameters. This part is currently discontinued at DiGi Electronics but maintains 10600 units in stock and is supplied in tube packaging. Use this option only when SN74HC21DR availability is constrained.

All three substitute parts maintain ROHS3 compliance and identical input/output electrical characteristics, ensuring direct circuit-level compatibility without design modification.

Frequently Asked Questions (FAQ)

Q: Can SN74HC21DR be used as a direct replacement for SN74HC21DG4?

A: Yes. The SN74HC21DR is electrically and functionally identical to the SN74HC21DG4. Both parts share the same logic type (dual 4-input AND gate), voltage supply range (2V ~ 6V), propagation delay (19ns @ 6V, 50pF), and 14-SOIC package. The primary difference is product status and packaging format. SN74HC21DR is currently active and available in cut tape and Digi-Reel formats.

Q: What is the difference between 14-SOIC and 14-SO packaging?

A: Both designations refer to the same 14-pin small outline IC package with 0.154" width and 3.90mm body width. The terms are used interchangeably in industry documentation. All substitute parts listed are compatible with PCB layouts designed for 14-SOIC packages.

Q: Why does 74HC21D,653 have a higher operating temperature range?

A: The 74HC21D,653 manufactured by Nexperia extends the maximum operating temperature to 125°C compared to 85°C for Texas Instruments versions. This reflects different manufacturer specifications for the same base logic function. All other electrical parameters remain identical.

Q: Are there any differences in input/output logic levels between substitute parts?

A: No. All substitute parts maintain identical input logic level specifications (Low: 0.5V ~ 1.8V; High: 1.5V ~ 4.2V) and output current ratings (5.2mA high/low). Logic threshold behavior is consistent across all listed alternatives.

Q: Which substitute part should be selected for new production designs?

A: SN74HC21DR is the recommended choice for new production due to active product status, high inventory availability (3590 units), and Texas Instruments manufacturing continuity. The part is available in standard cut tape and Digi-Reel packaging suitable for automated assembly processes.

Q: Is the 74HC21D,653 from Nexperia a suitable alternative?

A: Yes. The 74HC21D,653 is functionally equivalent with identical electrical specifications and offers extended temperature operation (-40°C to 125°C). This part is appropriate for applications requiring higher thermal margins or operation in elevated temperature environments. Nexperia is an established semiconductor manufacturer with ROHS3 compliance.

Q: What packaging formats are available for each substitute?

A: SN74HC21DR is supplied in cut tape (CT) and Digi-Reel formats. SN74HC21D is supplied in tube packaging. 74HC21D,653 is supplied in tape & reel (TR) format. Selection depends on assembly process requirements and order quantity.