FSUSB46L8X USB Switch IC Equivalent & Substitute Parts

Part Overview

The FSUSB46L8X is a USB Switch IC manufactured by onsemi, designed for high-speed USB 2.0 switching applications. This single-channel DPST (Double Pole Single Throw) switch operates at supply voltages between 3V and 4.3V with a maximum on-state resistance of 6.5Ω and supports bandwidth up to 720MHz. The component is currently classified as obsolete, making identification of functionally equivalent alternatives essential for ongoing system support and new design implementations.

Substiute Parts

FSUSB46L8X

onsemiIn Stock: 16563FSUSB46L8X Datasheet

Current PartRFQ

FSUSB31L8X

Fairchild SemiconductorIn Stock: 4236FSUSB31L8X Datasheet

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Key Parameters

Substitute Part Grouping Explanation

Substitution eligibility for the FSUSB46L8X is determined by strict alignment of the following critical parameters:

• Switch Circuit Type: Must be DPST to maintain identical switching topology
• Number of Channels: Must be 1 channel for functional equivalence
• Multiplexer/Demultiplexer Circuit: Must be 2:1 configuration
• Voltage Supply Range: Must support 3V ~ 4.3V single supply operation
• -3dB Bandwidth: Must support 720MHz minimum for USB 2.0 compliance
• Features: Must include Break-Before-Make and USB 2.0 support
• Operating Temperature Range: Must cover -40°C ~ 85°C (TA)
• Package / Case: Must be 8-UFQFN for PCB layout compatibility
• Supplier Device Package: Must be 8-MicroPak™

The FSUSB31L8X meets all substitution criteria and is classified as a direct equivalent for the obsolete FSUSB46L8X.

Parameter Comparison

Engineering Selection Recommendations

The FSUSB31L8X is an active product manufactured by Fairchild Semiconductor and serves as the direct functional equivalent for the obsolete FSUSB46L8X. Both components share identical electrical specifications across all critical parameters including supply voltage range, bandwidth, switching topology, and operating temperature range. The primary difference is on-state resistance, where the FSUSB31L8X specifies a maximum of 10Ω compared to 6.5Ω for the FSUSB46L8X. Both components comply with REACH regulations and carry identical ECCN and HTSUS classifications, confirming regulatory equivalence. The FSUSB31L8X is available in active inventory, making it the appropriate selection for replacement applications and new designs requiring USB 2.0 switching functionality in the 8-MicroPak™ package.

Frequently Asked Questions (FAQ)

Q: Can the FSUSB31L8X directly replace the FSUSB46L8X in existing designs?

A: Yes. Both components are pin-compatible 8-UFQFN packages with identical pinout and electrical interface specifications. PCB layout modifications are not required.

Q: What is the significance of the on-state resistance difference between these parts?

A: The FSUSB46L8X specifies 6.5Ω maximum on-state resistance while the FSUSB31L8X specifies 10Ω maximum. This difference affects signal insertion loss and power dissipation in switching applications. System designs must verify that the higher resistance of the FSUSB31L8X remains within acceptable performance margins for the specific application.

Q: Are there any regulatory or compliance differences between these parts?

A: No. Both components carry identical REACH status (REACH Unaffected), ECCN (EAR99), and HTSUS (8542.39.0001) classifications.

Q: Why is the FSUSB46L8X classified as obsolete?

A: The FSUSB46L8X has been discontinued by onsemi. The FSUSB31L8X from Fairchild Semiconductor provides equivalent functionality and is currently in active production.

Q: Are there any package or mounting differences?

A: No. Both components use the 8-UFQFN package format with 8-MicroPak™ supplier designation and surface mount technology. Footprint and reflow requirements are identical.