74FST3251DTR2 Equivalent & Substitute Parts

Part Overview

The 74FST3251DTR2 is a Multiplexer/Demultiplexer logic IC with a 1 x 8:1 circuit configuration, manufactured by onsemi in a 16-TSSOP surface mount package. This component is classified as Obsolete, making identification of suitable substitute parts essential for ongoing design support and procurement continuity. The functional equivalence of substitute parts enables direct replacement in applications requiring 8-to-1 multiplexing or demultiplexing operations within the specified electrical parameters.

Substiute Parts

74FST3251DTR2

onsemiIn Stock: 74274FST3251DTR2 Datasheet

Current PartRFQ

SN74CBT3251PW

Texas InstrumentsIn Stock: 2952SN74CBT3251PW Datasheet

DirectRFQ

SN74CBT3251PWR

Texas InstrumentsIn Stock: 45281SN74CBT3251PWR Datasheet

DirectRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitution of the 74FST3251DTR2 is determined by strict equivalence across the following parameters:

• Functional Type: Multiplexer/Demultiplexer with identical 1 x 8:1 circuit configuration
• Package Compatibility: 16-TSSOP surface mount package with matching physical dimensions (0.173", 4.40mm Width)
• Electrical Parameters: Single supply voltage operation within overlapping supply voltage ranges and identical operating temperature range (-40°C ~ 85°C)
• Moisture Sensitivity: MSL rating of 1 or better

The substitute parts SN74CBT3251PW and SN74CBT3251PWR, both manufactured by Texas Instruments, meet all substitution criteria. Both parts maintain the 74CBT series designation, confirming functional and electrical equivalence to the 74FST base product number.

Parameter Comparison

Engineering Selection Recommendations

SN74CBT3251PWR is the primary substitute for new designs and ongoing procurement. This part carries Active product status from Texas Instruments, ensuring long-term availability and supply chain stability. The part is ROHS3 compliant and available in high volume (45,200 pcs in stock), supplied in Cut Tape and Digi-Reel packaging formats suitable for automated assembly processes.

SN74CBT3251PW serves as a secondary substitute option. This part maintains Last Time Buy status, indicating limited future availability. It is ROHS3 compliant and available in Tube packaging (2,903 pcs in stock). This option is suitable for legacy system maintenance where existing inventory levels are adequate.

Both Texas Instruments substitutes operate within a narrower supply voltage range (4.5V ~ 5.5V) compared to the original 74FST3251DTR2 (4V ~ 5.5V). Applications requiring operation at 4V supply voltage must retain the original onsemi part or conduct electrical validation of the substitute under those conditions.

Frequently Asked Questions (FAQ)

Q: Can SN74CBT3251PW and SN74CBT3251PWR be used interchangeably?

A: Both parts are functionally equivalent and share identical electrical and mechanical specifications. The primary difference is product status and packaging format. SN74CBT3251PWR (Active status, Cut Tape/Digi-Reel) is preferred for new designs. SN74CBT3251PW (Last Time Buy, Tube) is suitable for legacy system support with adequate inventory planning.

Q: What is the impact of the narrower supply voltage range in the substitute parts?

A: The substitute parts operate at 4.5V ~ 5.5V, while the original operates at 4V ~ 5.5V. Applications designed for 4V operation must either retain the original 74FST3251DTR2 or conduct electrical validation of the substitute at the lower voltage threshold.

Q: Are the substitute parts pin-compatible with the original?

A: Yes. Both substitute parts use the identical 16-TSSOP package with matching pinout and physical dimensions (0.173", 4.40mm Width), enabling direct PCB replacement without layout modifications.

Q: What is the significance of RoHS compliance in the substitute parts?

A: The substitute parts are ROHS3 compliant, meeting current environmental and regulatory requirements for electronic components. The original 74FST3251DTR2 is RoHS non-compliant. New designs should specify the ROHS3-compliant substitutes to ensure regulatory compliance.

Q: Which substitute part should be selected for high-volume production?

A: SN74CBT3251PWR is the recommended choice for high-volume production. It carries Active product status, ensuring sustained manufacturing and supply availability. The Cut Tape and Digi-Reel packaging formats are optimized for automated pick-and-place assembly processes.