FST3126MTCX Equivalent & Substitute Parts

Part Overview

The FST3126MTCX is a bus switch logic IC manufactured by onsemi, configured as a 1 x 1:1 circuit with 4 independent circuits in a 14-TSSOP package. This component is classified as obsolete, making equivalent and substitute parts necessary for ongoing design support and procurement continuity. The FST3126MTCX operates with single supply voltage between 4V and 5.5V across an operating temperature range of -40°C to 85°C, suitable for surface mount applications requiring bus switching functionality.

Substiute Parts

FST3126MTCX

onsemiIn Stock: 35480FST3126MTCX Datasheet

Current PartRFQ

FST3125MTCX

onsemiIn Stock: 37870FST3125MTCX Datasheet

Parametric EquivalentRFQ

SN74CBT3126PW

Texas InstrumentsIn Stock: 3449SN74CBT3126PW Datasheet

DirectRFQ

SN74CBT3126DBR

Texas InstrumentsIn Stock: 2954SN74CBT3126DBR Datasheet

SimilarRFQ

SN74CBT3126PWR

Texas InstrumentsIn Stock: 5158SN74CBT3126PWR Datasheet

SimilarRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitution for the FST3126MTCX is determined by the following critical parameters: bus switch type with 1 x 1:1 circuit configuration, 4 independent circuits, single supply voltage operation within 4V to 5.5V range, operating temperature range of -40°C to 85°C, surface mount technology, and package compatibility. Substitute parts are grouped into three categories based on their relationship to the main part:

Parametric Equivalent: FST3125MTCX maintains identical electrical specifications and package dimensions, differing only in base product number and internal circuit design while preserving functional compatibility.

Direct Manufacturer Equivalent: SN74CBT3126PW (Texas Instruments) provides direct functional equivalence with identical circuit configuration, voltage supply range, and package type, though with different product status and compliance certifications.

Similar Alternatives: SN74CBT3126DBR and SN74CBT3126PWR offer functional equivalence with minor package variations (14-SSOP vs. 14-TSSOP) and different product statuses, suitable for applications where package footprint differences are acceptable.

Parameter Comparison

Engineering Selection Recommendations

For new designs and long-term procurement, SN74CBT3126PWR is the preferred substitute, as it maintains active product status with full ROHS3 compliance and identical electrical and package specifications to the FST3126MTCX. This part ensures supply continuity and regulatory compliance for current manufacturing.

For applications requiring immediate substitution with existing inventory, SN74CBT3126PW provides direct functional equivalence with identical package dimensions and electrical parameters, though it carries Last Time Buy status. This option is suitable for near-term production runs where supply is available.

FST3125MTCX serves as a parametric equivalent from onsemi with identical voltage supply range and operating temperature specifications. While both FST3126MTCX and FST3125MTCX are obsolete, FST3125MTCX offers higher current inventory (37,800 pcs) and ROHS3 compliance certification.

SN74CBT3126DBR is functionally equivalent but uses a 14-SSOP package (0.209", 5.30mm width) instead of 14-TSSOP (0.173", 4.40mm width). This substitute is applicable only when PCB layout accommodates the larger package footprint.

Frequently Asked Questions (FAQ)

Q: Can FST3125MTCX directly replace FST3126MTCX on existing PCBs?

A: Yes. FST3125MTCX maintains identical package dimensions (14-TSSOP, 0.173", 4.40mm width), voltage supply range (4V ~ 5.5V), operating temperature range (-40°C ~ 85°C), and circuit configuration (1 x 1:1 with 4 independent circuits). Both are surface mount components with MSL rating of 1 (Unlimited).

Q: What is the voltage supply difference between onsemi and Texas Instruments parts?

A: FST3126MTCX and FST3125MTCX specify 4V ~ 5.5V supply range, while Texas Instruments SN74CBT3126 series parts specify 4.5V ~ 5.5V. The Texas Instruments parts have a narrower lower voltage limit. Applications operating below 4.5V require the onsemi parts.

Q: Is SN74CBT3126DBR compatible with FST3126MTCX PCB layouts?

A: SN74CBT3126DBR uses a 14-SSOP package (0.209", 5.30mm width) compared to FST3126MTCX's 14-TSSOP package (0.173", 4.40mm width). Direct PCB substitution is not possible without layout modification. This part is suitable only for new designs or when PCB redesign is acceptable.

Q: Which substitute part has the best long-term availability?

A: SN74CBT3126PWR carries Active product status with 5,100 pcs in stock and ROHS3 compliance, making it the most suitable for long-term production requirements. All other alternatives are either Obsolete or Last Time Buy status.

Q: Are all substitute parts ROHS3 compliant?

A: FST3126MTCX compliance status is not specified in available data. FST3125MTCX, SN74CBT3126PW, SN74CBT3126DBR, and SN74CBT3126PWR are all ROHS3 compliant. For applications requiring ROHS3 certification, use Texas Instruments SN74CBT3126 series or onsemi FST3125MTCX.