FSUSB22BQX USB Switch IC Equivalent & Substitute Parts

Part Overview

The FSUSB22BQX is a quad-channel USB switch IC manufactured by onsemi, designed for USB 2.0 applications requiring 2:1 multiplexer/demultiplexer functionality with SPDT switching architecture. The device operates across a 3V to 3.6V single supply voltage range and features a 750MHz bandwidth with bi-directional switching capability in a 16-DQFN surface mount package.

The FSUSB22BQX is classified as obsolete. Identifying equivalent substitute parts is necessary to maintain design continuity, ensure supply chain availability, and support ongoing production requirements for applications currently utilizing this component.

Substiute Parts

FSUSB22BQX

onsemiIn Stock: 2052FSUSB22BQX Datasheet

Current PartRFQ

FSUSB42UMX

onsemiIn Stock: 285405FSUSB42UMX Datasheet

SimilarRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitution of the FSUSB22BQX is determined by the following critical parameters:

Electrical Compatibility Criteria:

• On-State Resistance: Maximum 6.5Ω (substitute must not exceed this value)
• Bandwidth: Minimum 720MHz (-3dB) to maintain signal integrity in USB 2.0 applications
• Supply Voltage: Substitute must operate within or encompass the 3V to 3.6V range
• Operating Temperature: Must support -40°C to 85°C range
• USB 2.0 compliance and bi-directional switching capability

Functional Criteria:

• Switch circuit architecture (SPDT or DPDT acceptable for single-channel operation)
• Surface mount packaging required
• Moisture Sensitivity Level 1 or equivalent

The FSUSB42UMX qualifies as a functional substitute based on matching on-state resistance (6.5Ω maximum), exceeding bandwidth requirements (720MHz), supporting an extended supply voltage range (2.4V to 4.4V, which encompasses the 3V to 3.6V requirement), and maintaining identical operating temperature specifications. The FSUSB42UMX operates as a single-channel DPDT switch with break-before-make functionality, providing equivalent switching performance for applications requiring individual channel control.

Parameter Comparison

Engineering Selection Recommendations

The FSUSB42UMX is the primary substitute for the obsolete FSUSB22BQX based on the following engineering criteria:

Product Status & Availability: The FSUSB42UMX maintains active product status with substantial inventory availability (285,300 pcs), ensuring long-term supply chain continuity compared to the obsolete FSUSB22BQX.

Regulatory Compliance: Both components share identical REACH and ECCN classifications (REACH Unaffected, EAR99), maintaining consistent export and regulatory compliance profiles. The FSUSB42UMX additionally carries RoHS3 compliance certification.

Electrical Performance: The FSUSB42UMX meets or exceeds all critical electrical parameters. The 720MHz bandwidth remains within acceptable tolerance for USB 2.0 applications (30MHz margin below the main part's 750MHz specification). The extended supply voltage range (2.4V to 4.4V) provides superior flexibility while maintaining compatibility with the original 3V to 3.6V operating window.

Functional Architecture: While the FSUSB22BQX provides four SPDT channels and the FSUSB42UMX provides one DPDT channel, the electrical switching characteristics remain equivalent. Applications requiring multiple independent channels would necessitate multiple FSUSB42UMX devices or alternative multi-channel solutions.

Frequently Asked Questions (FAQ)

Q: Can the FSUSB42UMX directly replace the FSUSB22BQX in all applications?

A: Direct replacement depends on channel requirements. The FSUSB22BQX provides four independent SPDT channels, while the FSUSB42UMX provides one DPDT channel. Applications requiring four simultaneous independent switches must implement four FSUSB42UMX devices or identify alternative quad-channel solutions. Single-channel or dual-channel applications can utilize the FSUSB42UMX directly.

Q: What is the significance of the DPDT versus SPDT architecture difference?

A: SPDT (Single Pole Double Throw) switches one input to one of two outputs. DPDT (Double Pole Double Throw) switches two independent inputs, each to one of two outputs. For single-channel switching applications, DPDT functionality encompasses SPDT capability. The FSUSB42UMX's break-before-make feature ensures no signal overlap during switching transitions.

Q: Are there package compatibility considerations?

A: Yes. The FSUSB22BQX uses a 16-WFQFN package (2.5x4.6mm), while the FSUSB42UMX uses a 10-UFQFN package (1.8x1.4mm). PCB layout modifications are required, including updated footprint design, trace routing, and via placement. The smaller FSUSB42UMX package may provide space optimization benefits.

Q: Does the extended supply voltage range of the FSUSB42UMX (2.4V to 4.4V) affect compatibility?

A: No. The extended range is a design advantage. The FSUSB42UMX operates reliably across the original 3V to 3.6V specification window while providing additional margin at lower voltages (2.4V to 3V) and higher voltages (3.6V to 4.4V). This does not compromise performance within the original operating range.

Q: What is the impact of the 30MHz bandwidth difference (750MHz vs. 720MHz)?

A: The 30MHz difference represents a 4% reduction and remains within acceptable tolerance for USB 2.0 applications, which operate at 480Mbps. Both devices exceed the bandwidth requirements for this application category by a significant margin.

Q: How does product status affect component selection?

A: The FSUSB22BQX's obsolete status indicates discontinued manufacturing and declining inventory availability. The FSUSB42UMX's active status ensures ongoing production, stable pricing, and reliable long-term supply chain access, making it the preferred choice for new designs and ongoing production support.