FSFR2100U Equivalent & Substitute Parts

Part Overview

The FSFR2100U is an offline switching half-bridge power management IC manufactured by onsemi, designed for isolated converter applications with topology support up to 300kHz switching frequency. This component is classified as obsolete, making identification of functionally equivalent alternatives essential for design continuity and procurement planning. The part operates within a 11.3V to 25V supply range and delivers up to 400W with integrated fault protection including current limiting, overload, overvoltage, and overtemperature monitoring.

Substiute Parts

FSFR2100U

onsemiIn Stock: 1941FSFR2100U Datasheet

Current PartRFQ

FSFR2100XS

onsemiIn Stock: 32784FSFR2100XS Datasheet

DirectRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitution eligibility for the FSFR2100U is determined by strict alignment of the following critical parameters:

• Topology: Half-Bridge configuration
• Output Isolation: Isolated operation
• Voltage - Breakdown: 500V minimum
• Voltage - Supply Range: Compatibility within or overlapping 11.3V ~ 25V
• Frequency - Switching: Up to 300kHz capability
• Power Rating: 400W minimum
• Duty Cycle: 50%
• Package / Case: 10-SIP Module, 9 Leads, Formed Leads
• Mounting Type: Through Hole

The FSFR2100XS qualifies as a direct substitute based on matching topology, isolation, breakdown voltage, switching frequency, power rating, duty cycle, package configuration, and mounting type. Variations in supply voltage range (10V ~ 25V vs. 11.3V ~ 25V) and startup voltage (12.5V vs. 14.5V) remain within acceptable operational margins for equivalent circuit design.

Parameter Comparison

Engineering Selection Recommendations

Both the FSFR2100U and FSFR2100XS are classified as obsolete products. The FSFR2100XS offers extended supply voltage range capability (10V minimum vs. 11.3V minimum) and lower startup voltage requirement (12.5V vs. 14.5V), providing operational flexibility in low-voltage supply scenarios. The FSFR2100U includes overload protection as an additional fault protection feature not specified for the FSFR2100XS.

The FSFR2100XS carries RoHS3 compliance certification, whereas the FSFR2100U status is not specified. Both parts maintain REACH Unaffected status and identical ECCN/HTSUS classifications. Packaging differs in that FSFR2100XS is supplied in tube format while FSFR2100U packaging is unspecified.

For new designs or long-term procurement, component selection should prioritize availability and compliance requirements specific to the application's regulatory environment.

Frequently Asked Questions (FAQ)

Q: Can FSFR2100XS directly replace FSFR2100U in existing designs?

A: Yes, the FSFR2100XS qualifies as a direct substitute based on matching topology, isolation, voltage breakdown, switching frequency, power rating, duty cycle, and package configuration. The lower startup voltage and extended supply range of the FSFR2100XS provide operational compatibility across the FSFR2100U's specified supply window.

Q: What is the significance of the supply voltage range difference?

A: The FSFR2100XS operates from 10V minimum compared to FSFR2100U's 11.3V minimum. This expanded lower range allows operation in applications with tighter supply margins. Both parts support the same 25V maximum, ensuring compatibility within standard offline converter supply specifications.

Q: Are there differences in fault protection between these parts?

A: The FSFR2100U specifies overload protection in addition to current limiting, overvoltage, and overtemperature protection. The FSFR2100XS omits explicit overload protection specification. Circuit design should account for this distinction when overload protection is a critical design requirement.

Q: What packaging considerations apply to substitution?

A: Both parts use identical 10-SIP Module, 9 Leads, Formed Leads package with through-hole mounting. No PCB layout or assembly process modifications are required for substitution. The FSFR2100XS is supplied in tube packaging format.

Q: Why are both parts classified as obsolete?

A: Obsolete status indicates these components are no longer in active production. Procurement should prioritize available inventory from authorized distributors. The FSFR2100XS maintains significantly higher inventory availability (32,749 pcs) compared to FSFR2100U (1,900 pcs).