FST3126MX Bus Switch 1 x 1:1 Equivalent & Substitute Parts

Part Overview

The FST3126MX is a bus switch IC manufactured by onsemi, designed for 1 x 1:1 switching applications in logic circuits. This component features a single supply voltage range of 4V to 5.5V and operates across an industrial temperature range of -40°C to 85°C. The part is housed in a 14-SOIC surface mount package with four independent circuits.

The FST3126MX is classified as obsolete. Identifying equivalent and substitute parts is necessary to maintain design continuity, ensure supply chain availability, and support ongoing production requirements for legacy systems utilizing this bus switch topology.

Substiute Parts

FST3126MX

onsemiIn Stock: 6090FST3126MX Datasheet

Current PartRFQ

FST3126DR2G

onsemiIn Stock: 2246FST3126DR2G Datasheet

UpgradeRFQ

SN74CBT3126D

Texas InstrumentsIn Stock: 3671SN74CBT3126D Datasheet

DirectRFQ

SN74CBT3126DR

Texas InstrumentsIn Stock: 3573SN74CBT3126DR Datasheet

SimilarRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitute parts for the FST3126MX are qualified based on the following electrical and mechanical parameters:

Critical Matching Parameters:

• Circuit configuration: 1 x 1:1 topology with 4 independent circuits
• Package type: 14-SOIC surface mount form factor
• Voltage supply source: Single supply operation
• Mounting compatibility: Surface mount technology

Allowable Parameter Variations:

• Voltage supply range: Substitutes may operate at 4.5V ~ 5.5V (subset of original 4V ~ 5.5V range)
• Operating temperature range: Substitutes may extend to -55°C ~ 125°C (wider range than original -40°C ~ 85°C)
• Packaging format: Tube or Tape & Reel (TR) formats are functionally equivalent
• Manufacturer: Texas Instruments (74CBT series) and onsemi (FST series) parts are cross-compatible
• Product status: Last Time Buy or Obsolete status does not affect functional substitution

Parameter Comparison

Engineering Selection Recommendations

FST3126DR2G (onsemi) is the direct upgrade path from FST3126MX. Both parts are manufactured by onsemi and share identical electrical specifications within the 4V ~ 5.5V supply range. FST3126DR2G extends the operating temperature range to -55°C ~ 125°C and carries ROHS3 compliance certification. This part is available in Tape & Reel packaging format.

SN74CBT3126D (Texas Instruments) provides cross-manufacturer compatibility with identical 1 x 1:1 circuit topology and 14-SOIC packaging. The supply voltage range is constrained to 4.5V ~ 5.5V, which is a subset of the original specification. This part maintains Last Time Buy status and ROHS3 compliance. Tube packaging is the standard format.

SN74CBT3126DR (Texas Instruments) is functionally equivalent to SN74CBT3126D with identical electrical parameters and Tape & Reel packaging format. This variant is suitable for high-volume production environments requiring automated component handling.

Selection between onsemi and Texas Instruments substitutes depends on supply chain availability, existing inventory management practices, and compliance documentation requirements. All three substitute parts maintain the critical 1 x 1:1 circuit topology, 4 independent circuits, and 14-SOIC package form factor required for direct substitution.

Frequently Asked Questions (FAQ)

Q: Can FST3126DR2G replace FST3126MX in all applications?

A: FST3126DR2G is functionally equivalent to FST3126MX for applications operating within the 4V ~ 5.5V supply range and -40°C ~ 85°C temperature window. FST3126DR2G extends both specifications, providing additional margin for extended temperature operation (-55°C ~ 125°C). Pin-to-pin compatibility and circuit topology are identical.

Q: What is the difference between SN74CBT3126D and SN74CBT3126DR?

A: Both parts are electrically identical with the same 1 x 1:1 circuit configuration, 4 independent circuits, and 14-SOIC package. The primary difference is packaging format: SN74CBT3126D is supplied in Tube format, while SN74CBT3126DR is supplied in Tape & Reel (TR) format. Tape & Reel packaging is optimized for automated assembly processes.

Q: Are there voltage supply differences between FST3126MX and the Texas Instruments substitutes?

A: FST3126MX operates at 4V ~ 5.5V supply voltage. SN74CBT3126D and SN74CBT3126DR operate at 4.5V ~ 5.5V. The Texas Instruments parts do not support operation at 4V supply voltage. Applications requiring 4V operation must use FST3126DR2G or the original FST3126MX.

Q: What does ROHS3 compliance mean for these bus switch parts?

A: ROHS3 compliance indicates the part meets Restriction of Hazardous Substances Directive requirements, restricting the use of specific hazardous materials in electrical and electronic equipment. FST3126DR2G, SN74CBT3126D, and SN74CBT3126DR all carry ROHS3 certification. FST3126MX compliance status is not specified in available documentation.

Q: Can I use these bus switch parts interchangeably in production?

A: All four parts (FST3126MX, FST3126DR2G, SN74CBT3126D, SN74CBT3126DR) share identical 1 x 1:1 circuit topology, 4 independent circuits, and 14-SOIC package geometry. Interchangeability is confirmed for the specified electrical and mechanical parameters. Verify supply voltage requirements and operating temperature range for your specific application before substitution.

Q: What is the Moisture Sensitivity Level (MSL) for these parts?

A: All four parts carry MSL rating of 1 (Unlimited), indicating unlimited shelf life without moisture control requirements. These components do not require special moisture-sensitive device handling procedures during storage or assembly.