74FST3126DTR2 Equivalent & Substitute Parts

Part Overview

The 74FST3126DTR2 is a bus switch IC manufactured by onsemi, designed for 1 x 1:1 switching applications in logic circuits. This component features 4 independent circuits and operates across a single supply voltage range of 4V to 5.5V with an operating temperature range of -40°C to 85°C. The part is packaged in a 14-TSSOP surface mount configuration.

The 74FST3126DTR2 is classified as obsolete, which necessitates identification of equivalent and substitute parts for ongoing design support and procurement. Substitute parts must maintain functional equivalence through matching circuit topology, electrical parameters, and mechanical compatibility.

Substiute Parts

74FST3126DTR2

onsemiIn Stock: 78874FST3126DTR2 Datasheet

Current PartRFQ

FST3125MTCX

onsemiIn Stock: 37870FST3125MTCX Datasheet

Parametric EquivalentRFQ

SN74CBT3126PW

Texas InstrumentsIn Stock: 3449SN74CBT3126PW Datasheet

DirectRFQ

SN74CBT3126PWR

Texas InstrumentsIn Stock: 5158SN74CBT3126PWR Datasheet

DirectRFQ

SN74CBT3126DBR

Texas InstrumentsIn Stock: 2954SN74CBT3126DBR Datasheet

SimilarRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitution of the 74FST3126DTR2 is determined by the following critical parameters:

Functional Equivalence: Circuit topology (1 x 1:1 configuration with 4 independent circuits) must be identical.

Electrical Compatibility: Voltage supply range (4V ~ 5.5V minimum), operating temperature range (-40°C ~ 85°C), and single supply source requirement must be maintained or exceeded.

Mechanical Compatibility: Package type (14-TSSOP or compatible surface mount package) and pin configuration must support direct substitution or require minimal board-level adaptation.

Compliance Status: RoHS compliance and REACH status are documented for regulatory tracking but do not restrict functional substitution.

Substitute parts are grouped into three categories based on substitution relationship:

Parametric Equivalent: FST3125MTCX maintains identical functional specifications with improved RoHS3 compliance and higher inventory availability.

Direct Manufacturer Equivalents: SN74CBT3126PW and SN74CBT3126PWR are Texas Instruments equivalents with identical circuit topology and package specifications. SN74CBT3126PWR is currently active in production.

Similar Configuration: SN74CBT3126DBR provides functional equivalence with a package variant (14-SSOP vs. 14-TSSOP), requiring verification of PCB footprint compatibility.

Parameter Comparison

Engineering Selection Recommendations

For Active Production Designs: SN74CBT3126PWR is the recommended primary substitute. This part is currently active in production status, offers ROHS3 compliance, maintains identical electrical and mechanical specifications, and provides the highest long-term availability assurance. The 4.5V minimum supply voltage is compatible with standard 5V logic systems.

For Existing Inventory Replacement: FST3125MTCX provides a high-inventory alternative (37,800 pcs available) with parametric equivalence and ROHS3 compliance. The onsemi manufacturer maintains design continuity while offering improved regulatory compliance compared to the obsolete 74FST3126DTR2.

For Last-Time-Buy Scenarios: SN74CBT3126PW offers direct equivalence with Last Time Buy status, suitable for designs requiring immediate substitution without production transition delays.

For Package-Variant Applications: SN74CBT3126DBR provides functional equivalence with a 14-SSOP package variant (0.209" width vs. 0.173" for TSSOP). PCB footprint compatibility must be verified before selection, as the wider package may require layout modifications.

Regulatory Compliance Consideration: All recommended substitutes provide ROHS3 compliance, addressing regulatory requirements that the obsolete 74FST3126DTR2 does not meet.

Frequently Asked Questions (FAQ)

Q: Can SN74CBT3126PWR directly replace 74FST3126DTR2 without circuit modifications?

A: Yes. Both parts maintain identical circuit topology (1 x 1:1 configuration with 4 independent circuits), operating temperature range (-40°C to 85°C), and 14-TSSOP package specifications. The SN74CBT3126PWR supply voltage range (4.5V ~ 5.5V) is compatible with the original specification (4V ~ 5.5V) in standard 5V logic applications.

Q: What is the difference between FST3125MTCX and 74FST3126DTR2?

A: FST3125MTCX is a parametric equivalent with identical electrical specifications and package type. The primary differences are manufacturer series designation (FST3125 vs. 74FST3126), product status (Obsolete for both), and RoHS compliance (ROHS3 Compliant vs. non-compliant). Inventory availability is significantly higher for FST3125MTCX (37,800 pcs vs. 772 pcs).

Q: Why does SN74CBT3126DBR have a different package designation?

A: SN74CBT3126DBR uses a 14-SSOP package (0.209" width) compared to the 14-TSSOP package (0.173" width) of the original part. Both are surface mount packages with identical pin counts and electrical specifications. PCB footprint compatibility must be verified, as the wider SSOP package may not fit existing TSSOP layouts without modification.

Q: Are all substitute parts RoHS compliant?

A: All recommended substitutes (FST3125MTCX, SN74CBT3126PW, SN74CBT3126PWR, and SN74CBT3126DBR) are ROHS3 compliant. The original 74FST3126DTR2 is RoHS non-compliant. Compliance status should be verified against your design requirements and regional regulations.

Q: Which substitute offers the best long-term availability?

A: SN74CBT3126PWR is the optimal choice for long-term availability, as it maintains Active product status with Texas Instruments. FST3125MTCX offers the highest current inventory (37,800 pcs) but is classified as Obsolete. Both SN74CBT3126PW and SN74CBT3126DBR are Last Time Buy, indicating limited future availability.

Q: What is the minimum supply voltage for substitute parts?

A: SN74CBT3126PWR, SN74CBT3126PW, and SN74CBT3126DBR specify a minimum supply voltage of 4.5V. FST3125MTCX maintains the original 4V minimum. For designs operating below 4.5V, FST3125MTCX is the appropriate selection.