FSUSB42UMX USB Switch IC Equivalent & Substitute Parts

Part Overview

The FSUSB42UMX is an active USB switch IC manufactured by onsemi, designed for single-channel USB 2.0 switching applications. This DPDT (Double Pole Double Throw) switch IC operates across a 2.4V to 4.4V supply range with a maximum on-state resistance of 6.5Ohm and -3dB bandwidth of 720MHz. The device is housed in a 10-UMLP surface mount package (1.8x1.4mm) and is currently in active product status with ROHS3 compliance and unlimited moisture sensitivity rating.

Equivalent and substitute parts are necessary when the primary part becomes unavailable, when alternative packaging or performance characteristics better suit specific application requirements, or when design optimization requires components with different electrical parameters within acceptable operating ranges.

Key Parameters

Parameter	FSUSB42UMX
Manufacturer	onsemi
Product Status	Active
Switch Circuit Type	DPDT
Number of Channels	1
On-State Resistance (Max)	6.5Ohm
Voltage Supply Range (V+)	2.4V ~ 4.4V
-3dB Bandwidth	720MHz
Operating Temperature	-40°C ~ 85°C
Package Type	10-UMLP (1.8x1.4mm)
Features	Break-Before-Make, USB 2.0
RoHS Status	ROHS3 Compliant
MSL Rating	1 (Unlimited)

Substitute Part Grouping Explanation

Substitution eligibility for the FSUSB42UMX is determined by the following critical parameters:

Primary Substitution Criteria:

Switch circuit configuration: DPDT topology
Single channel operation
USB 2.0 application compatibility
On-state resistance within acceptable range (6.5Ohm to 12Ohm maximum)
Supply voltage overlap with 2.4V ~ 4.4V range
Surface mount packaging in 10-pin miniature form factor
Operating temperature range: -40°C ~ 85°C minimum
ROHS3 compliance and MSL 1 rating

Identified Substitute Groups:

Group 1 - Direct Functional Equivalents (Active Status): NX3DV42GU10X and NX3DV42GU,115 from NXP USA Inc. maintain identical DPDT single-channel topology with 6.5Ohm on-state resistance and Break-Before-Make functionality. Both support USB 2.0 with extended operating temperature to 125°C and higher -3dB bandwidth (950MHz).

Group 2 - Compatible Alternatives (Obsolete Status): NLAS7222BMUTBG and NLAS7242MUTBG from onsemi provide DPDT single-channel switching with USB 2.0 support but are marked obsolete. NLAS7222BMUTBG has 12Ohm on-state resistance with narrower supply range (3V ~ 3.6V). NLAS7242MUTBG offers 8.5Ohm resistance with wider supply range (1.65V ~ 4.5V) and superior bandwidth (950MHz).

Group 3 - Alternative Topology (Active Status): DG2730DN-T1-GE4 from Vishay Siliconix provides DPDT switching with 8Ohm on-state resistance and 2:2 multiplexer configuration. Supply range 2.7V ~ 4.3V overlaps with FSUSB42UMX, with 900MHz bandwidth and additional performance metrics including switch time and crosstalk specifications.

Parameter Comparison

Parameter	FSUSB42UMX	NX3DV42GU10X	NX3DV42GU,115	NLAS7222BMUTBG	NLAS7242MUTBG	DG2730DN-T1-GE4
Manufacturer	onsemi	NXP USA Inc.	NXP USA Inc.	onsemi	onsemi	Vishay Siliconix
Product Status	Active	Active	Active	Obsolete	Obsolete	Active
Switch Circuit	DPDT	DPDT	DPDT	DPDT	DPDT	DPDT
Number of Channels	1	1	1	1	1	1
On-State Resistance (Max)	6.5Ohm	6.5Ohm	6.5Ohm	12Ohm	8.5Ohm	8Ohm
Voltage Supply (V+)	2.4V ~ 4.4V	3V ~ 4.3V	3V ~ 4.3V	3V ~ 3.6V	1.65V ~ 4.5V	2.7V ~ 4.3V
-3dB Bandwidth	720MHz	950MHz	950MHz	750MHz	950MHz	900MHz
Operating Temperature	-40°C ~ 85°C	-40°C ~ 125°C	-40°C ~ 125°C	-40°C ~ 85°C	-40°C ~ 85°C	-40°C ~ 85°C
Package Type	10-UMLP (1.8x1.4mm)	10-XQFN (1.3x1.6mm)	10-XQFN (1.4x1.8mm)	10-UQFN (1.4x1.8mm)	10-UQFN (1.4x1.8mm)	10-miniQFN (1.4x1.8mm)
Features	Break-Before-Make, USB 2.0	Break-Before-Make, USB 2.0	Break-Before-Make, USB 2.0	USB 2.0	USB 2.0	USB 2.0
RoHS Status	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant
MSL Rating	1 (Unlimited)	1 (Unlimited)	1 (Unlimited)	1 (Unlimited)	1 (Unlimited)	1 (Unlimited)

Engineering Selection Recommendations

For Active Product Status Requirement: NX3DV42GU10X and NX3DV42GU,115 are the primary recommendations as both maintain active product status with full manufacturer support. These NXP devices provide identical on-state resistance (6.5Ohm) and Break-Before-Make functionality with extended operating temperature range to 125°C. DG2730DN-T1-GE4 from Vishay Siliconix is also active status and offers comparable performance with 8Ohm on-state resistance.

For Supply Voltage Compatibility: NLAS7242MUTBG provides the widest supply voltage range (1.65V ~ 4.5V), accommodating applications requiring lower voltage operation. NX3DV42GU10X and NX3DV42GU,115 operate within 3V ~ 4.3V, which overlaps the FSUSB42UMX range above 3V. DG2730DN-T1-GE4 operates 2.7V ~ 4.3V, providing broader low-voltage coverage than the NXP alternatives.

For Bandwidth Performance: NLAS7242MUTBG, NX3DV42GU10X, and NX3DV42GU,115 all provide 950MHz -3dB bandwidth, exceeding the FSUSB42UMX specification of 720MHz. DG2730DN-T1-GE4 provides 900MHz bandwidth. These higher bandwidth specifications support applications with more demanding signal integrity requirements.

For On-State Resistance: NX3DV42GU10X and NX3DV42GU,115 match the FSUSB42UMX at 6.5Ohm. DG2730DN-T1-GE4 provides 8Ohm resistance. NLAS7242MUTBG offers 8.5Ohm. NLAS7222BMUTBG has the highest resistance at 12Ohm and is not recommended for applications sensitive to insertion loss.

For Compliance and Reliability: All substitute parts maintain ROHS3 compliance and MSL 1 (unlimited) rating, matching the FSUSB42UMX environmental and regulatory requirements. Obsolete parts (NLAS7222BMUTBG and NLAS7242MUTBG) should be avoided for new designs requiring long-term manufacturer support.

Frequently Asked Questions (FAQ)

Q: Can NLAS7222BMUTBG or NLAS7242MUTBG be used as direct replacements despite obsolete status?

A: These parts maintain functional DPDT topology and USB 2.0 compatibility with ROHS3 compliance. However, obsolete status indicates discontinued manufacturer support and potential supply chain limitations. Use only when active alternatives are unavailable and supply chain risk is acceptable.

Q: What is the impact of different on-state resistance values on circuit performance?

A: On-state resistance directly affects insertion loss and signal attenuation. The FSUSB42UMX at 6.5Ohm provides baseline performance. NX3DV42GU10X and NX3DV42GU,115 match this specification. DG2730DN-T1-GE4 at 8Ohm and NLAS7242MUTBG at 8.5Ohm introduce slightly higher insertion loss. NLAS7222BMUTBG at 12Ohm produces the most significant attenuation and is suitable only for applications with relaxed signal integrity requirements.

Q: Are package size differences between 10-UMLP, 10-UQFN, 10-XQFN, and 10-miniQFN critical for PCB layout?

A: Package footprints differ in dimensions and pin pitch. FSUSB42UMX uses 10-UMLP (1.8x1.4mm). Substitute parts use 10-UQFN (1.4x1.8mm), 10-XQFN (1.3x1.6mm or 1.4x1.8mm), or 10-miniQFN (1.4x1.8mm). PCB layout and routing must be redesigned for each package variant. Verify footprint compatibility with design tools before component selection.

Q: Which substitute provides the best temperature performance?

A: NX3DV42GU10X and NX3DV42GU,115 extend operating temperature to -40°C ~ 125°C, compared to FSUSB42UMX at -40°C ~ 85°C. This 40°C extended upper limit supports high-temperature applications. All other substitutes maintain the -40°C ~ 85°C range matching the primary part.

Q: Is Break-Before-Make functionality available in all substitutes?

A: Break-Before-Make is specified for FSUSB42UMX, NX3DV42GU10X, and NX3DV42GU,115. NLAS7222BMUTBG, NLAS7242MUTBG, and DG2730DN-T1-GE4 do not list this feature in provided specifications. Verify break-before-make requirement with application circuit design before selecting alternatives.

Q: What supply voltage range should be used for multi-supply applications?

A: Select the substitute with supply range that encompasses all required operating voltages. NLAS7242MUTBG provides the widest range (1.65V ~ 4.5V). For applications operating above 3V, NX3DV42GU10X and NX3DV42GU,115 are suitable. For applications requiring 2.4V minimum, DG2730DN-T1-GE4 (2.7V minimum) or FSUSB42UMX (2.4V minimum) are required.

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