FST34X2245QSPX Equivalent & Substitute Parts

Part Overview

The FST34X2245QSPX is an 8 x 1:1 bus switch IC manufactured by onsemi in a 80-QVSOP surface mount package. This component functions as a logic-level bus switch for signal routing and multiplexing applications. The part is classified as obsolete, making identification of functionally equivalent alternatives necessary for ongoing design support and procurement planning.

Substiute Parts

FST34X2245QSPX

onsemiIn Stock: 941FST34X2245QSPX Datasheet

Current PartRFQ

SN74CBT34X245DBBR

Texas InstrumentsIn Stock: 3381SN74CBT34X245DBBR Datasheet

SimilarRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitution of the FST34X2245QSPX is determined by the following critical parameters:

• Circuit Configuration: 8 x 1:1 bus switch topology
• Independent Circuits: 4 independent switching channels
• Voltage Supply Range: Single supply operation within 4V to 5.5V envelope
• Operating Temperature: -40°C to 85°C industrial range
• Mounting Type: Surface mount technology
• Package Classification: 80-pin thin shrink small outline package variants

The SN74CBT34X245DBBR from Texas Instruments meets these core functional and electrical requirements. While package dimensions differ (80-TFSOP vs. 80-QVSOP), both are 80-pin thin shrink packages suitable for surface mount assembly. The substitute maintains identical circuit topology, voltage supply specifications, and temperature operating range.

Parameter Comparison

Engineering Selection Recommendations

The SN74CBT34X245DBBR is the primary equivalent for the obsolete FST34X2245QSPX. Selection is justified on the following basis:

Functional Equivalence: Both parts implement identical 8 x 1:1 bus switch architecture with 4 independent circuits, ensuring pin-level and functional compatibility at the logic interface.

Electrical Compatibility: Operating temperature range is identical (-40°C to 85°C). The substitute's voltage supply range (4.5V ~ 5.5V) is a subset of the original (4V ~ 5.5V), suitable for standard 5V logic supply applications.

Active Product Status: The Texas Instruments part is in active production, ensuring long-term availability and supply chain continuity compared to the obsolete onsemi device.

Regulatory Compliance: Both parts carry identical REACH and ECCN classifications (REACH Unaffected, EAR99), with matching moisture sensitivity levels (MSL 1).

Package Consideration: The substitute uses 80-TSSOP packaging (0.240" width) versus the original 80-QVSOP (0.154" width). PCB layout modification is required to accommodate the wider package footprint.

Frequently Asked Questions (FAQ)

Q: Can the SN74CBT34X245DBBR directly replace the FST34X2245QSPX without circuit modification?

A: Electrical and functional compatibility is confirmed. PCB layout modification is necessary due to package width difference (80-TFSOP at 6.10mm versus 80-QVSOP at 3.90mm). Pin assignments and signal integrity characteristics are equivalent.

Q: What is the voltage supply difference between these parts?

A: The original FST34X2245QSPX operates from 4V to 5.5V. The substitute SN74CBT34X245DBBR operates from 4.5V to 5.5V. For applications using standard 5V supply, both parts are compatible. Applications requiring 4V to 4.5V operation require the original part or alternative sourcing.

Q: Why is the FST34X2245QSPX classified as obsolete?

A: Obsolete status indicates the manufacturer has discontinued production. The Texas Instruments equivalent remains in active production, providing a viable path for ongoing component procurement and design support.

Q: Are there package-related considerations for PCB assembly?

A: Yes. The 80-TSSOP package is wider (6.10mm) than the 80-QVSOP (3.90mm). Existing PCB layouts designed for the onsemi part require footprint and routing modifications. Thermal and electrical performance characteristics remain equivalent.

Q: What certifications apply to both parts?

A: Both parts are REACH Unaffected and classified as EAR99 for export control purposes. Moisture sensitivity level is identical (MSL 1, Unlimited). RoHS3 compliance is confirmed for the Texas Instruments substitute.