TOP245FN Equivalent & Substitute Parts

Part Overview

The TOP245FN is an offline switch flyback converter IC manufactured by Power Integrations, designed for isolated power supply applications. This device operates in the TOPSwitch®-GX series and delivers up to 85 W of power using flyback topology with integrated frequency control and comprehensive fault protection. The TOP245FN is classified as obsolete, making identification of suitable substitute components necessary for new designs and ongoing production support. The part is available in TO-262-7 through-hole packaging and maintains full RoHS compliance.

Substiute Parts

TOP245FN

Power IntegrationsIn Stock: 36354TOP245FN Datasheet

Current PartRFQ

TOP267KG-TL

Power IntegrationsIn Stock: 1432TOP267KG-TL Datasheet

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Key Parameters

Substitute Part Grouping Explanation

Substitution of the TOP245FN requires evaluation of the following critical parameters that determine functional compatibility:

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

Voltage Rating: The breakdown voltage must meet or exceed the original specification (700V minimum) to ensure safe operation under maximum input voltage conditions.

Power Capacity: The substitute must deliver sufficient power output. The TOP245FN provides 85 W; substitutes with lower power ratings may not support the intended application load.

Switching Frequency: Operating frequency range must overlap with or encompass the original 66kHz to 132kHz specification to maintain transformer design compatibility and EMI characteristics.

Fault Protection: The substitute must include equivalent or enhanced protection mechanisms (current limiting, over-temperature, over-voltage) to ensure system reliability.

Operating Temperature Range: The substitute must support the full -40°C to 150°C junction temperature range.

Compliance and Status: Active product status and maintained RoHS compliance are required for new designs and long-term supply assurance.

Parameter Comparison

Engineering Selection Recommendations

TOP267KG-TL as Substitute for TOP245FN

The TOP267KG-TL is classified as an active product from Power Integrations' TOPSwitch®-JX series and represents a viable substitute for the obsolete TOP245FN in new design implementations. Both devices share identical topology (isolated flyback), matching operating temperature range (-40°C to 150°C), and overlapping switching frequency specifications (66kHz and 132kHz).

The TOP267KG-TL provides enhanced fault protection with the addition of over-load and short-circuit detection beyond the current-limiting, over-temperature, and over-voltage protection present in the TOP245FN. The breakdown voltage is increased to 725V, providing additional margin above the TOP245FN's 700V rating.

Critical Design Consideration: The TOP267KG-TL delivers 65 W maximum power output compared to the TOP245FN's 85 W. Applications requiring the full 85 W capacity of the original part cannot be directly substituted without circuit redesign or load reduction. The duty cycle differs (78% versus 66.5%), which affects transformer design parameters and must be evaluated during circuit adaptation.

Packaging Transition: The TOP245FN uses through-hole TO-262-7 packaging, while the TOP267KG-TL employs surface-mount 12-BESOP packaging. PCB layout and assembly process modifications are required for this substitution.

Compliance Status: Both parts maintain RoHS compliance and REACH unaffected status, supporting regulatory requirements for new production.

Frequently Asked Questions (FAQ)

Q: Can the TOP267KG-TL directly replace the TOP245FN without circuit modifications?

A: Direct pin-for-pin replacement is not possible due to different package types (TO-262-7 through-hole versus 12-BESOP surface-mount). Additionally, the reduced power rating (65 W versus 85 W) and different duty cycle (78% versus 66.5%) require circuit evaluation. Applications operating below 65 W may proceed with circuit adaptation; higher-power applications require alternative solutions.

Q: What are the key electrical differences between these parts?

A: The TOP267KG-TL features a higher breakdown voltage (725V versus 700V), enhanced fault protection including over-load and short-circuit detection, and a higher duty cycle (78% versus 66.5%). The switching frequency range overlaps at 66kHz and 132kHz. The primary limitation is reduced power capacity (65 W versus 85 W).

Q: Why is the TOP245FN classified as obsolete?

A: The TOP245FN belongs to the TOPSwitch®-GX series, which has been superseded by newer generations such as the TOPSwitch®-JX series (represented by the TOP267KG-TL). Power Integrations has transitioned product lines to newer architectures offering improved performance and protection features.

Q: Are there packaging considerations for substitution?

A: Yes. The TOP245FN is a through-hole component (TO-262-7), while the TOP267KG-TL is surface-mount (12-BESOP). This requires PCB redesign, different assembly processes, and updated manufacturing procedures. Through-hole and surface-mount designs are not interchangeable without complete board layout revision.

Q: What protection features does the TOP267KG-TL add compared to the TOP245FN?

A: The TOP267KG-TL includes over-load and short-circuit protection in addition to the current-limiting, over-temperature, and over-voltage protection present in the TOP245FN. These additional protections enhance system reliability and fault response.

Q: Is the TOP267KG-TL suitable for applications requiring 85 W output?

A: No. The TOP267KG-TL is rated for 65 W maximum power. Applications requiring the full 85 W capacity of the TOP245FN must either reduce load requirements to 65 W or identify alternative components with higher power ratings.

Q: Do both parts support the same operating temperature range?

A: Yes. Both the TOP245FN and TOP267KG-TL operate across the identical junction temperature range of -40°C to 150°C, ensuring compatibility for applications with extended temperature requirements.