FSUSB46K8X USB Switch IC Equivalent & Substitute Parts

Part Overview

The FSUSB46K8X is a USB Switch IC manufactured by onsemi, designed for single-channel USB 2.0 switching applications. This component features a DPST (Double Pole Single Throw) switch configuration with Break-Before-Make functionality, operating across a 3V to 4.3V supply range. The part is classified as obsolete, making identification of functionally equivalent alternatives essential for ongoing design support and component procurement.

Substiute Parts

FSUSB46K8X

onsemiIn Stock: 1336FSUSB46K8X Datasheet

Current PartRFQ

FSUSB31K8X

onsemiIn Stock: 4575FSUSB31K8X Datasheet

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Key Parameters

Substitute Part Grouping Explanation

Substitution eligibility for the FSUSB46K8X is determined by the following critical parameters:

• Switch Configuration: DPST topology with Break-Before-Make functionality
• Channel Count: Single channel (1 channel)
• Supply Voltage Range: 3V ~ 4.3V compatibility
• Bandwidth Performance: 720MHz -3dB bandwidth for USB 2.0 signal integrity
• Package Compatibility: 8-VFSOP surface mount package with identical physical dimensions
• Operating Temperature: -40°C ~ 85°C range
• Feature Set: USB 2.0 compliance and Break-Before-Make switching behavior

The FSUSB31K8X meets all substitution criteria within the allowed parameter tolerance for on-state resistance variation, maintaining functional equivalence for USB switching applications.

Parameter Comparison

Engineering Selection Recommendations

Both the FSUSB46K8X and FSUSB31K8X are classified as obsolete products. Selection between these components should be based on the following criteria:

On-State Resistance Consideration: The FSUSB46K8X specifies a maximum on-state resistance of 6.5Ω, while the FSUSB31K8X specifies 10Ω. For applications where signal integrity and minimal insertion loss are critical, the lower resistance of the FSUSB46K8X is preferable. However, both values remain within acceptable ranges for standard USB 2.0 switching applications.

Compliance and Certifications: The FSUSB31K8X carries RoHS3 compliance certification, whereas the FSUSB46K8X does not specify this status. Both parts are REACH Unaffected and classified under ECCN EAR99.

Inventory Availability: The FSUSB31K8X has higher inventory availability (4474 Pcs) compared to the FSUSB46K8X (1240 Pcs), which may influence procurement decisions for volume requirements.

Frequently Asked Questions (FAQ)

Q: Can the FSUSB31K8X directly replace the FSUSB46K8X in existing designs?

A: Yes, the FSUSB31K8X is functionally equivalent for USB 2.0 switching applications. Both components share identical switch topology (DPST), channel configuration (1 channel), supply voltage range (3V ~ 4.3V), bandwidth (720MHz), package type (8-VFSOP), and operating temperature range (-40°C ~ 85°C). The primary difference is on-state resistance specification (10Ω vs. 6.5Ω), which remains within acceptable parameters for standard USB switching.

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

A: On-state resistance affects signal insertion loss and power dissipation during switching. The FSUSB46K8X's lower 6.5Ω specification provides marginally better signal integrity compared to the FSUSB31K8X's 10Ω specification. For most USB 2.0 applications, both values are acceptable. Applications requiring minimal insertion loss should prioritize the lower resistance value.

Q: Are both parts suitable for new designs?

A: Both the FSUSB46K8X and FSUSB31K8X are classified as obsolete. For new designs, evaluation of current-generation USB switch ICs from onsemi or alternative manufacturers is recommended to ensure long-term component availability and support.

Q: What does the 8-VFSOP package specification mean?

A: The 8-VFSOP (Very Fine Pitch Small Outline Package) is a surface mount package with 8 pins, measuring 0.091 inches (2.30mm) in width. Both substitute parts use identical packaging, ensuring PCB layout and footprint compatibility without design modifications.

Q: Is the Break-Before-Make feature present in both parts?

A: Yes, both the FSUSB46K8X and FSUSB31K8X incorporate Break-Before-Make switching functionality. This feature ensures the switch disconnects the previous signal path before establishing a new connection, preventing signal contention and data corruption during switching transitions.