FSFR1800L Equivalent & Substitute Parts

Part Overview

The FSFR1800L is an offline switching half-bridge power management IC manufactured by onsemi, designed for isolated converter applications with up to 300kHz switching frequency and 260W power handling capability. The device features integrated fault protection including current limiting, overload, overvoltage, and overtemperature detection. Due to its obsolete product status, equivalent substitute parts are available to maintain design continuity and ensure supply chain reliability for applications requiring half-bridge topology offline converters.

Substiute Parts

FSFR1800L

onsemiIn Stock: 1710FSFR1800L Datasheet

Current PartRFQ

FSFR1800XS

onsemiIn Stock: 6489FSFR1800XS Datasheet

SimilarRFQ

FSFR1800XSL

Fairchild SemiconductorIn Stock: 2665FSFR1800XSL Datasheet

SimilarRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitute parts for the FSFR1800L are qualified based on the following critical parameters that determine functional equivalence:

Core Substitution Criteria:

• Topology: Half-Bridge configuration
• Output Isolation: Isolated
• Voltage - Breakdown: 500V minimum
• Frequency - Switching: Up to 300kHz capability
• Power (Watts): 260W rating
• Duty Cycle: 50%
• Package / Case: 10-SIP Module, 9 Leads, Formed Leads
• Mounting Type: Through Hole
• Operating Temperature Range: -40°C ~ 130°C (TJ)

Acceptable Parameter Variations:

• Voltage - Supply (Vcc/Vdd): Range may vary within operational limits (10V ~ 25V acceptable)
• Voltage - Start Up: May differ within practical startup requirements
• Fault Protection: Subset of protection features acceptable if core protections present
• Control Features: May vary in implementation
• Product Status: Active or Obsolete both acceptable for substitution purposes
• Compliance Certifications: REACH and RoHS status may differ

Parameter Comparison

Engineering Selection Recommendations

FSFR1800XS is a direct functional equivalent to FSFR1800L. Both devices share identical topology, power rating, switching frequency, and thermal operating range. The FSFR1800XS features a lower startup voltage (12.5V vs 14.5V) and expanded supply voltage range (10V ~ 25V vs 11.3V ~ 25V), providing operational flexibility. The FSFR1800XS omits overload protection compared to the main part but retains current limiting, overvoltage, and overtemperature protection. Both parts are obsolete; however, FSFR1800XS maintains higher inventory availability (6418 pcs vs 1629 pcs).

FSFR1800XSL is manufactured by Fairchild Semiconductor with active product status, offering long-term supply assurance. This part maintains the same package configuration and through-hole mounting as the FSFR1800L. Detailed electrical parameters are not fully specified in available documentation; however, the part is listed as a direct substitute within the FSFR1800 base product family. The active status makes this option suitable for new designs or applications requiring extended component lifecycle support.

For applications where supply continuity is critical, FSFR1800XSL is preferred due to active product status. For immediate availability, FSFR1800XS is the optimal choice based on parameter alignment and inventory levels.

Frequently Asked Questions (FAQ)

Q: Can FSFR1800XS directly replace FSFR1800L in existing designs?

A: Yes. Both parts share identical half-bridge topology, 500V breakdown voltage, 260W power rating, 300kHz switching frequency, 50% duty cycle, and -40°C to 130°C operating temperature range. The FSFR1800XS features a lower startup voltage (12.5V vs 14.5V) and broader supply range (10V ~ 25V vs 11.3V ~ 25V). The primary difference is omission of overload protection in the FSFR1800XS; current limiting, overvoltage, and overtemperature protections remain intact.

Q: What is the difference between FSFR1800XS and FSFR1800XSL?

A: Both are qualified substitutes for FSFR1800L. FSFR1800XS is manufactured by onsemi with obsolete status. FSFR1800XSL is manufactured by Fairchild Semiconductor with active product status, providing extended supply availability. Package configuration and mounting type are identical for both parts.

Q: Why is FSFR1800L marked as obsolete?

A: Product obsolescence indicates the manufacturer has discontinued active production. Substitute parts within the FSFR1800 base product family remain available to support existing applications and designs.

Q: Are there packaging differences between these parts?

A: All three parts use 10-SIP Module with 9 Leads and Formed Leads in through-hole mounting configuration. FSFR1800XS is supplied in Tube packaging; FSFR1800L and FSFR1800XSL packaging specifications are not detailed but maintain the same physical form factor.

Q: What compliance certifications apply to these parts?

A: All three parts maintain REACH Unaffected status. FSFR1800XS is ROHS3 Compliant. FSFR1800L has Moisture Sensitivity Level 1 (Unlimited). FSFR1800XSL has Vendor Undefined MSL classification.

Q: Which part should be selected for new designs?

A: FSFR1800XSL is recommended for new designs due to active product status, ensuring long-term availability and supply chain stability. FSFR1800XS is suitable for replacement applications where immediate availability is prioritized.