TOP249FN Equivalent & Substitute Parts

Part Overview

The TOP249FN is an offline flyback converter IC from Power Integrations' TOPSwitch®-GX series, designed for isolated power supply applications with 250W output capability. This component integrates a high-voltage switch with comprehensive protection features including current limiting, over-temperature, and over-voltage monitoring. The part operates across a switching frequency range of 66kHz to 132kHz and is housed in a TO-262-7C through-hole package.

The TOP249FN is classified as obsolete. Identifying suitable substitute components is necessary to support ongoing design requirements, system maintenance, and production continuity where original inventory becomes unavailable.

Substiute Parts

TOP249FN

Power IntegrationsIn Stock: 2374TOP249FN Datasheet

Current PartRFQ

TOP271KG-TL

Power IntegrationsIn Stock: 2283TOP271KG-TL Datasheet

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Key Parameters

Substitute Part Grouping Explanation

Substitution of the TOP249FN requires evaluation against the following critical parameters that define functional equivalence:

Topology & Isolation: Both the main part and substitute must operate as isolated flyback converters with internal switching capability.

Voltage Rating: The substitute must maintain a breakdown voltage rating sufficient for the application. The TOP249FN specifies 700V; acceptable substitutes must meet or exceed this specification.

Switching Frequency: The TOP249FN operates at 66kHz to 132kHz. Substitutes must support compatible frequency ranges to maintain system timing and transformer design compatibility.

Power Capability: The TOP249FN is rated for 250W output. Substitutes must be capable of delivering equivalent or greater power levels for the intended application.

Fault Protection: The TOP249FN includes current limiting, over-temperature, and over-voltage protection. Substitutes must provide equivalent or enhanced protection features.

Compliance & Status: The substitute must maintain RoHS compliance and REACH compliance status. Active product status is preferred for long-term availability.

The TOP271KG-TL from Power Integrations' TOPSwitch®-JX series qualifies as a substitute based on shared topology, isolation characteristics, compatible switching frequencies, and enhanced protection features. However, the TOP271KG-TL operates at a lower maximum power rating (102W versus 250W) and uses a different package type (12-ESOP surface mount versus TO-262-7 through hole).

Parameter Comparison

Engineering Selection Recommendations

Product Status Consideration: The TOP249FN is classified as obsolete, while the TOP271KG-TL maintains active product status. Active status ensures continued manufacturer support, availability of technical documentation, and potential process improvements.

Compliance Verification: Both components maintain RoHS compliance and REACH unaffected status, satisfying regulatory requirements for most applications.

Power Rating Differential: The TOP271KG-TL is rated for 102W maximum output, compared to the TOP249FN's 250W rating. Applications requiring the full 250W capability cannot be directly substituted without circuit redesign or parallel configurations.

Package & Mounting Transition: The TOP249FN uses through-hole TO-262-7 packaging, while the TOP271KG-TL uses surface-mount 12-ESOP packaging. PCB layout and assembly process modifications are required for substitution.

Protection Feature Enhancement: The TOP271KG-TL provides additional over-load and short-circuit protection compared to the TOP249FN, offering enhanced system reliability.

Voltage Rating: The TOP271KG-TL's 725V breakdown voltage exceeds the TOP249FN's 700V specification, maintaining adequate margin for high-voltage applications.

Frequently Asked Questions (FAQ)

Q: Can the TOP271KG-TL directly replace the TOP249FN in existing designs?

A: Direct replacement is not possible without circuit modifications. The TOP271KG-TL has a lower power rating (102W versus 250W), different package type (surface mount versus through hole), and different pin configuration. PCB redesign and component layout changes are required.

Q: What is the primary limitation of using TOP271KG-TL as a substitute?

A: The maximum power output of 102W is significantly lower than the TOP249FN's 250W rating. Applications designed for 250W operation cannot use the TOP271KG-TL without reducing system power requirements or implementing alternative topologies.

Q: Are both components compatible with the same switching frequency requirements?

A: Both components support 66kHz and 132kHz switching frequencies, providing frequency compatibility. However, the TOP249FN supports continuous operation across the 66kHz to 132kHz range, while the TOP271KG-TL operates at discrete frequency points.

Q: What are the package compatibility implications?

A: The TOP249FN uses through-hole TO-262-7 packaging for PCB insertion mounting. The TOP271KG-TL uses surface-mount 12-ESOP packaging requiring solder reflow assembly. These mounting methods are incompatible without complete PCB redesign.

Q: Do both components provide equivalent protection features?

A: The TOP271KG-TL provides enhanced protection with over-load and short-circuit detection in addition to the current limiting, over-temperature, and over-voltage protection found in the TOP249FN.

Q: Is the TOP271KG-TL suitable for applications requiring 250W output?

A: No. The TOP271KG-TL is rated for maximum 102W output. Applications requiring 250W operation must either retain the TOP249FN through alternative sourcing channels or implement alternative power management solutions.

Q: What compliance certifications apply to both components?

A: Both the TOP249FN and TOP271KG-TL maintain RoHS compliance and REACH unaffected status, satisfying standard regulatory requirements for electronic components in most markets.