SN74121DR Equivalent & Substitute Parts

Part Overview

The SN74121DR is a monostable multivibrator logic IC manufactured by Texas Instruments, housed in a 14-SOIC surface mount package. This component features dual independent circuits with a 45 ns propagation delay and operates within the standard 5V logic supply range. The SN74121DR is classified as obsolete, making identification of compatible substitute parts essential for ongoing design support and procurement planning. Active equivalent parts maintain identical electrical and mechanical specifications while offering current manufacturing status and improved supply chain availability.

Substiute Parts

SN74121DR

Texas InstrumentsIn Stock: 4015SN74121DR Datasheet

Current PartRFQ

SN74121D

Texas InstrumentsIn Stock: 2152SN74121D Datasheet

DirectRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitute parts for the SN74121DR are identified based on strict equivalence across the following critical parameters:

• Logic Type: Monostable Multivibrator
• Independent Circuits: 2
• Propagation Delay: 45 ns
• Current - Output High, Low: 400µA, 16mA
• Voltage - Supply: 4.75 V ~ 5.25 V
• Operating Temperature: 0°C ~ 70°C
• Package / Case: 14-SOIC (0.154", 3.90mm Width)
• Mounting Type: Surface Mount

The SN74121D qualifies as a direct substitute, maintaining identical electrical performance and mechanical compatibility while offering active product status and current manufacturing availability.

Parameter Comparison

Engineering Selection Recommendations

The SN74121D serves as the primary substitute for the obsolete SN74121DR. Both parts maintain identical electrical specifications and mechanical compatibility, with pin-for-pin equivalence in the 14-SOIC package. The SN74121D offers the advantage of active product status, ensuring continued manufacturing support and supply chain availability. Both parts carry ROHS3 compliance and identical moisture sensitivity ratings, supporting equivalent environmental and regulatory requirements. Selection between these parts should be based on procurement availability and supply chain considerations, as electrical performance and board-level compatibility are fully equivalent.

Frequently Asked Questions (FAQ)

Q: Can the SN74121D directly replace the SN74121DR in existing designs?

A: Yes. The SN74121D is electrically and mechanically equivalent to the SN74121DR. Both parts feature identical propagation delay, output current specifications, supply voltage range, operating temperature range, and 14-SOIC package dimensions. Direct substitution requires no circuit modifications.

Q: What is the primary difference between these parts?

A: The SN74121DR is classified as obsolete, while the SN74121D maintains active product status. This distinction affects long-term availability and manufacturing support, not electrical or mechanical performance.

Q: Are there packaging differences between the SN74121DR and SN74121D?

A: Both parts use the 14-SOIC surface mount package with identical dimensions (0.154" width, 3.90mm). The SN74121D is supplied in tube packaging, while the SN74121DR packaging type was not specified. This does not affect electrical compatibility or board-level integration.

Q: Do both parts meet the same compliance standards?

A: Yes. Both the SN74121DR and SN74121D are ROHS3 compliant with identical moisture sensitivity levels (MSL 1 - Unlimited), supporting equivalent environmental and regulatory requirements.

Q: Which part should be selected for new designs?

A: The SN74121D should be selected for new designs due to its active product status, ensuring continued manufacturing availability and supply chain support.