FSUSB23BQX USB Switch IC Equivalent & Substitute Parts

Part Overview

The FSUSB23BQX is a USB Switch IC manufactured by onsemi, designed for single-channel USB 2.0 switching applications. This component features a DPDT (Double Pole Double Throw) switch circuit in a 16-DQFN package with 2.5x4.6mm dimensions. The product is currently classified as obsolete, making identification of functionally equivalent alternatives essential for ongoing design support and component procurement.

Substiute Parts

FSUSB23BQX

onsemiIn Stock: 1372FSUSB23BQX Datasheet

Current PartRFQ

FSUSB42UMX

onsemiIn Stock: 285405FSUSB42UMX Datasheet

SimilarRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitution of the FSUSB23BQX is determined by the following critical electrical and mechanical parameters:

Primary Substitution Criteria:

• Switch circuit configuration: DPDT topology
• Number of channels: Single channel (1)
• Bandwidth performance: 720 MHz minimum
• USB 2.0 compliance
• Operating temperature range: -40°C ~ 85°C
• Supply voltage compatibility or overlap with 3V ~ 3.6V range
• On-state resistance: Maximum 10 Ohm (lower values acceptable)
• Surface mount packaging with compatible pin count and electrical interface

The FSUSB42UMX qualifies as a direct substitute based on matching all primary criteria while offering improved electrical performance characteristics and active product status.

Parameter Comparison

Engineering Selection Recommendations

The FSUSB42UMX is the qualified substitute for the obsolete FSUSB23BQX based on the following factors:

Electrical Compatibility: The FSUSB42UMX maintains identical switch circuit topology (DPDT), channel count (1), and bandwidth performance (720 MHz). The supply voltage range of 2.4V ~ 4.4V encompasses the original 3V ~ 3.6V specification, ensuring full compatibility with existing power supply designs. The reduced on-state resistance (6.5 Ohm versus 10 Ohm maximum) represents an improvement in electrical performance.

Product Status & Availability: The FSUSB42UMX holds active product status with substantial inventory availability (285,300 pcs), whereas the FSUSB23BQX is obsolete. This transition ensures long-term component supply continuity and manufacturing support.

Compliance & Certifications: Both components maintain identical MSL ratings (1 - Unlimited), REACH status (REACH Unaffected), and ECCN classification (EAR99). The FSUSB42UMX additionally carries RoHS3 compliance certification.

Package Consideration: The FSUSB42UMX uses a 10-UFQFN package (1.8x1.4mm) compared to the 16-WFQFN package (2.5x4.6mm) of the original part. PCB layout redesign is required to accommodate the different pin configuration and package footprint.

Frequently Asked Questions (FAQ)

Q: Can the FSUSB42UMX directly replace the FSUSB23BQX without circuit modifications?

A: Electrical substitution is valid based on matching DPDT topology, single-channel configuration, 720 MHz bandwidth, and USB 2.0 compliance. However, the different package types (16-WFQFN versus 10-UFQFN) require PCB layout redesign. Pin-to-pin correspondence must be verified against the respective datasheets before implementation.

Q: What is the significance of the Break-Before-Make feature in the FSUSB42UMX?

A: Break-Before-Make is an additional feature in the FSUSB42UMX that ensures the switch disconnects the previous connection before establishing a new one. This characteristic is not specified for the FSUSB23BQX but does not create incompatibility; it represents enhanced switching behavior suitable for USB applications.

Q: Is the wider supply voltage range (2.4V ~ 4.4V) of the FSUSB42UMX a concern?

A: No. The FSUSB42UMX supply range fully encompasses the original 3V ~ 3.6V specification. The extended range provides greater design flexibility and compatibility with varied power supply implementations without compromising performance within the original operating window.

Q: What are the package footprint implications of substitution?

A: The FSUSB23BQX uses a 16-pin DQFN package (2.5x4.6mm), while the FSUSB42UMX uses a 10-pin UFQFN package (1.8x1.4mm). The reduced pin count and smaller footprint require complete PCB redesign. Verify pin assignments and signal routing compatibility with the FSUSB42UMX datasheet before layout implementation.

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

A: Both components share identical REACH status (REACH Unaffected) and ECCN classification (EAR99). The FSUSB42UMX carries additional RoHS3 compliance certification. Both maintain MSL 1 (Unlimited) moisture sensitivity ratings, ensuring equivalent handling and storage requirements.