74FST3251DR2 Equivalent & Substitute Parts

Part Overview

The 74FST3251DR2 is a Multiplexer/Demultiplexer logic IC with a 1 x 8:1 circuit configuration, manufactured by onsemi in a 16-SOIC surface mount package. This component is classified as obsolete, making identification of suitable substitute parts essential for ongoing design support and production continuity. The part operates within a single supply voltage range of 4V to 5.5V and supports operating temperatures from -40°C to 85°C.

Substiute Parts

74FST3251DR2

onsemiIn Stock: 93674FST3251DR2 Datasheet

Current PartRFQ

SN74CBT3251D

Texas InstrumentsIn Stock: 1944SN74CBT3251D Datasheet

DirectRFQ

SN74CBT3251DR

Texas InstrumentsIn Stock: 2149SN74CBT3251DR Datasheet

DirectRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitute parts for the 74FST3251DR2 are qualified based on the following critical parameters that determine functional and mechanical compatibility:

Functional Parameters:

• Circuit type and configuration (Multiplexer/Demultiplexer 1 x 8:1)
• Independent circuit count (1)
• Voltage supply source (Single Supply)
• Voltage supply range compatibility (minimum 4V operation required)
• Operating temperature range (-40°C to 85°C)

Mechanical Parameters:

• Package type (16-SOIC)
• Package dimensions (0.154", 3.90mm Width)
• Mounting type (Surface Mount)
• Supplier device package (16-SOIC)

The identified substitute parts SN74CBT3251D and SN74CBT3251DR meet all functional and mechanical requirements. Both parts maintain the 1 x 8:1 multiplexer/demultiplexer configuration, operate within compatible voltage ranges (4.5V ~ 5.5V), support the required temperature range, and are packaged in identical 16-SOIC form factors.

Parameter Comparison

Engineering Selection Recommendations

SN74CBT3251DR (Primary Recommendation): This Texas Instruments part carries Active product status, ensuring long-term availability and manufacturing support. It is ROHS3 compliant, meeting current regulatory requirements. The part is supplied in Cut Tape and Digi-Reel packaging formats with 2114 units in current inventory. The voltage supply range of 4.5V to 5.5V is compatible with the original 74FST3251DR2 specification when operating within the 4.5V minimum threshold.

SN74CBT3251D (Secondary Option): This Texas Instruments alternative maintains Last Time Buy status, indicating limited future availability. It is ROHS3 compliant and available in Tube packaging with 1900 units in inventory. This part is suitable for applications where the higher minimum voltage specification (4.5V) does not present operational constraints.

Both substitute parts provide functional and mechanical equivalence to the obsolete 74FST3251DR2, with the primary distinction being product lifecycle status and packaging format.

Frequently Asked Questions (FAQ)

Q: Can SN74CBT3251D and SN74CBT3251DR be used interchangeably with 74FST3251DR2?

A: Both Texas Instruments parts are functionally and mechanically equivalent to the 74FST3251DR2. They share identical circuit configurations (1 x 8:1 multiplexer/demultiplexer), package types (16-SOIC), and operating temperature ranges (-40°C to 85°C). The primary consideration is the minimum voltage specification: the substitutes require 4.5V minimum, whereas the original part operates from 4V minimum.

Q: What is the difference between SN74CBT3251D and SN74CBT3251DR?

A: Both parts are manufactured by Texas Instruments with identical electrical specifications and package dimensions. The difference lies in product status and packaging format. SN74CBT3251DR is Active status with Cut Tape and Digi-Reel packaging, while SN74CBT3251D is Last Time Buy status with Tube packaging. For new designs, SN74CBT3251DR is preferred due to its active lifecycle status.

Q: Are there any compliance differences between the original and substitute parts?

A: The 74FST3251DR2 is RoHS non-compliant, while both substitute parts (SN74CBT3251D and SN74CBT3251DR) are ROHS3 compliant. All three parts maintain REACH Unaffected status. If RoHS compliance is required for your application, the Texas Instruments substitutes satisfy this requirement.

Q: Will the 4.5V minimum voltage specification of the substitutes affect my circuit?

A: The substitute parts require a minimum supply voltage of 4.5V, compared to the original part's 4V minimum. If your circuit operates at voltages below 4.5V, the substitutes are not suitable. For circuits operating at 4.5V or higher within the 5.5V maximum, the substitutes are fully compatible.

Q: What is the moisture sensitivity level for these parts?

A: All three parts—74FST3251DR2, SN74CBT3251D, and SN74CBT3251DR—have a Moisture Sensitivity Level (MSL) of 1 (Unlimited), indicating no moisture sensitivity restrictions during storage or handling.