FSFR1800XSL Equivalent & Substitute Parts

Part Overview

The FSFR1800XSL is an offline switching half-bridge power management IC manufactured by onsemi, designed for isolated converter applications with switching frequencies up to 300kHz. This component operates with a 260W power rating and integrates internal switches with comprehensive fault protection including current limiting, over-temperature, and over-voltage monitoring.

The FSFR1800XSL is classified as obsolete. Identifying equivalent and substitute parts is necessary to ensure design continuity, maintain supply chain reliability, and support long-term product availability for applications currently utilizing this component.

Substiute Parts

FSFR1800XSL

onsemiIn Stock: 2668FSFR1800XSL Datasheet

Current PartRFQ

FSFR1800XS

onsemiIn Stock: 6489FSFR1800XS Datasheet

SimilarRFQ

FSFR1700XS

Fairchild SemiconductorIn Stock: 1584FSFR1700XS Datasheet

Parametric EquivalentRFQ

FSFR1700XSL

Fairchild SemiconductorIn Stock: 16531FSFR1700XSL Datasheet

Parametric EquivalentRFQ

FSFR2100XS

onsemiIn Stock: 32784FSFR2100XS Datasheet

Parametric EquivalentRFQ

FSFR2100XSL

onsemiIn Stock: 1219FSFR2100XSL Datasheet

Parametric EquivalentRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitute parts for the FSFR1800XSL are determined by strict equivalence across the following critical parameters:

• Topology: Half-Bridge configuration
• Voltage - Breakdown: 500V
• Voltage - Supply (Vcc/Vdd): 10V ~ 25V
• Voltage - Start Up: 12.5V
• Frequency - Switching: Up to 300kHz
• Duty Cycle: 50%
• Output Isolation: Isolated
• Internal Switch(s): Yes
• Fault Protection: Current Limiting, Over Temperature, Over Voltage
• Control Features: Frequency Control
• Operating Temperature: -40°C ~ 130°C (TJ)
• Package / Case: 10-SIP Module, 9 Leads, Formed Leads
• Mounting Type: Through Hole

Substitute parts are grouped into two categories:

Direct Substitutes (Identical Electrical and Mechanical Parameters):

• FSFR1800XS: Identical specifications with 9-SIP packaging (non-formed leads variant)

Parametric Equivalents (Matching Core Electrical Parameters with Power Rating Variations):

• FSFR1700XS / FSFR1700XSL: 200W power rating (lower capacity)
• FSFR2100XS / FSFR2100XSL: 400W power rating (higher capacity)

All substitute parts maintain identical topology, voltage ratings, switching frequency, protection features, and operating temperature range.

Parameter Comparison

Engineering Selection Recommendations

For Direct Replacement (Identical Specifications):

FSFR1800XS is the direct substitute for FSFR1800XSL. Both components share identical electrical specifications and 260W power rating. The primary difference is the lead forming variant (L forming vs. standard). Both are ROHS3 compliant and obsolete status. This substitution maintains full functional equivalence.

For Parametric Equivalents with Lower Power Capacity:

FSFR1700XS and FSFR1700XSL are parametric equivalents with 200W power rating. These parts are currently in active product status, providing improved long-term availability. Selection of these parts is appropriate for applications where the 260W capacity of the FSFR1800XSL exceeds system requirements. Both FSFR1700 variants maintain all electrical parameters, topology, and protection features. FSFR1700XSL includes L forming leads matching the original FSFR1800XSL package variant.

For Parametric Equivalents with Higher Power Capacity:

FSFR2100XS and FSFR2100XSL are parametric equivalents with 400W power rating. These parts provide increased power handling capability while maintaining all core electrical specifications and protection features. Both variants are ROHS3 compliant. FSFR2100XSL includes L forming leads. Selection of these parts is appropriate for applications requiring higher power capacity or where future design margin is necessary.

Compliance Considerations:

All recommended substitutes maintain ROHS3 compliance and EAR99 export classification. REACH status is unaffected across all variants. Moisture sensitivity level (MSL) is 1 (Unlimited) for the FSFR1800XSL and FSFR1800XS, providing maximum handling flexibility.

Frequently Asked Questions (FAQ)

Q: Can FSFR1800XS directly replace FSFR1800XSL?

A: Yes. FSFR1800XS is a direct substitute with identical electrical specifications, 260W power rating, and through-hole mounting. The difference is the lead forming variant. FSFR1800XS uses standard 9-SIP packaging while FSFR1800XSL uses 9-SIP with L forming leads. Both are functionally equivalent.

Q: What is the difference between FSFR1700 and FSFR1800 variants?

A: The primary difference is power rating. FSFR1700 series is rated for 200W while FSFR1800 series is rated for 260W. All other electrical parameters, topology, voltage ratings, switching frequency, and protection features are identical. FSFR1700 variants are currently in active product status, providing better long-term availability.

Q: Can FSFR2100 series replace FSFR1800XSL?

A: FSFR2100 series (400W rating) is a parametric equivalent with identical electrical specifications and protection features. It can replace FSFR1800XSL in applications where higher power capacity is acceptable or beneficial. The increased power rating does not create compatibility issues in circuits designed for 260W operation.

Q: What does "L forming" mean in the package designation?

A: L forming refers to the lead configuration. FSFR1800XSL and FSFR1700XSL use formed leads (L forming), while FSFR1800XS, FSFR1700XS, FSFR2100XS use standard leads. Both configurations are through-hole mounted and mechanically compatible with standard PCB footprints designed for 9-SIP packages.

Q: Are all substitute parts ROHS3 compliant?

A: FSFR1800XSL, FSFR1800XS, FSFR2100XS, and FSFR2100XSL are ROHS3 compliant. FSFR1700XS and FSFR1700XSL do not specify RoHS status in the provided data. Verify RoHS compliance requirements with the component manufacturer or distributor if this is a critical specification for your application.

Q: Which substitute offers the best long-term availability?

A: FSFR1700XS and FSFR1700XSL are in active product status, providing superior long-term availability compared to the obsolete FSFR1800XSL, FSFR1800XS, FSFR2100XS, and FSFR2100XSL. For new designs or long-term supply chain planning, FSFR1700 variants are recommended.

Q: Can I use FSFR1700 in a design originally specified for FSFR1800XSL?

A: Yes, if your application power requirements do not exceed 200W. FSFR1700 series maintains all electrical specifications, topology, voltage ratings, switching frequency, and protection features. The lower power rating is the only functional difference. Verify that your circuit's maximum power demand does not exceed 200W before substitution.