TOP248FN Equivalent & Substitute Parts

Part Overview

The TOP248FN is an offline flyback converter IC from Power Integrations' TOPSwitch®-GX series, designed for isolated power supply applications. This device integrates a 700V breakdown voltage switch with comprehensive fault protection including current limiting, over-temperature, and over-voltage monitoring. The part operates at switching frequencies between 66kHz and 132kHz with a maximum power rating of 205W.

The TOP248FN is classified as obsolete. Identifying suitable substitute components is necessary to maintain design continuity, ensure supply chain availability, and support ongoing production requirements for applications currently utilizing this topology.

Substiute Parts

TOP248FN

Power IntegrationsIn Stock: 25819TOP248FN Datasheet

Current PartRFQ

TOP270KG-TL

Power IntegrationsIn Stock: 3623TOP270KG-TL Datasheet

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Key Parameters

Substitute Part Grouping Explanation

Substitution of the TOP248FN requires evaluation based on the following critical parameters:

Topology & Isolation: Both the main part and substitute must maintain flyback topology with isolated output configuration to preserve circuit functionality.

Voltage Rating: The substitute must meet or exceed the 700V breakdown voltage specification to ensure safe operation across the intended input voltage range.

Switching Frequency: The substitute must operate within or overlap the 66kHz to 132kHz frequency band to maintain compatibility with existing transformer and filter designs.

Power Rating: The substitute power rating must be sufficient for the application. The TOP248FN is rated at 205W; substitutes with lower power ratings require design verification.

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

Package & Mounting: Physical package compatibility affects PCB layout and thermal management. Through-hole and surface-mount packages are not directly interchangeable without redesign.

Compliance & Status: Active product status ensures ongoing availability and manufacturer support. RoHS compliance and REACH status must be maintained.

Parameter Comparison

Engineering Selection Recommendations

TOP270KG-TL as Substitute for TOP248FN

The TOP270KG-TL is an active product from Power Integrations' TOPSwitch®-JX series and maintains core functional compatibility with the TOP248FN in flyback topology and isolated output configuration. Both devices operate within overlapping switching frequency ranges (66kHz, 132kHz) and share identical operating temperature specifications (-40°C ~ 150°C).

Compatibility Considerations:

The TOP270KG-TL features a higher breakdown voltage (725V vs. 700V), which provides additional margin for input voltage transients. The substitute includes enhanced fault protection with short-circuit detection in addition to the current limiting, over-temperature, and over-voltage protection present in the TOP248FN.

Design Impact:

The TOP270KG-TL is rated at 91W maximum power, compared to the TOP248FN's 205W rating. Applications requiring the full 205W output power cannot use this substitute without additional design modifications or parallel configurations.

The TOP270KG-TL uses a 12-BESOP surface-mount package with 11 leads and exposed pad, whereas the TOP248FN uses a TO-262-7 through-hole package with 6 leads. PCB layout redesign is required for package migration.

Compliance Status:

Both devices maintain RoHS compliance and REACH unaffected status. The TOP270KG-TL's active product status ensures continued manufacturer support, technical documentation, and supply availability, addressing the obsolescence of the TOP248FN.

Frequently Asked Questions (FAQ)

Q: Can the TOP270KG-TL directly replace the TOP248FN without PCB modifications?

A: No. The TOP270KG-TL uses a 12-BESOP surface-mount package while the TOP248FN uses a TO-262-7 through-hole package. PCB layout redesign is required. Additionally, the pinout differs (11 leads vs. 6 leads), necessitating schematic and layout changes.

Q: What is the power rating limitation when using TOP270KG-TL as a substitute?

A: The TOP270KG-TL is rated at 91W maximum power output, compared to the TOP248FN's 205W rating. Applications designed for 205W operation cannot use this substitute without design modifications to reduce output power requirements or implement alternative topologies.

Q: Are the switching frequency ranges compatible between these devices?

A: Both devices support 66kHz and 132kHz switching frequencies. The TOP248FN operates across a continuous range (66kHz ~ 132kHz), while the TOP270KG-TL operates at discrete frequencies (66kHz, 132kHz). Existing transformer and filter designs optimized for the continuous frequency range may require adjustment.

Q: What additional protection features does the TOP270KG-TL provide?

A: The TOP270KG-TL includes short-circuit protection in addition to the current limiting, over-temperature, and over-voltage protection found in the TOP248FN. This enhanced protection is suitable for applications requiring higher reliability margins.

Q: Are both devices RoHS compliant?

A: Yes. Both the TOP248FN and TOP270KG-TL are RoHS compliant and REACH unaffected, meeting current environmental and regulatory requirements.

Q: Why is the TOP248FN classified as obsolete?

A: The TOP248FN belongs to the older TOPSwitch®-GX series. Power Integrations has transitioned to newer series such as TOPSwitch®-JX (represented by the TOP270KG-TL), which offer enhanced features, improved protection, and continued manufacturing support.

Q: What is the duty cycle difference between these devices?

A: The TOP248FN operates at 66.8% duty cycle, while the TOP270KG-TL operates at 78% duty cycle. This difference affects transformer design and output voltage regulation characteristics and must be accounted for during circuit redesign.

Q: Is the TOP270KG-TL available in through-hole packaging?

A: No. The TOP270KG-TL is available only in 12-BESOP surface-mount package. If through-hole mounting is required, alternative substitutes from Power Integrations' product line must be evaluated.