TOP242FN Equivalent & Substitute Parts Reference

Part Overview

The TOP242FN 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 22W of power using flyback topology with integrated frequency control and comprehensive fault protection. The TOP242FN is classified as obsolete, making identification of suitable substitute components essential for design continuity and procurement planning. Alternative parts must maintain functional equivalence in topology, isolation characteristics, and protection features while accommodating differences in packaging and electrical ratings.

Substiute Parts

TOP242FN

Power IntegrationsIn Stock: 8097TOP242FN Datasheet

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TOP264KG-TL

Power IntegrationsIn Stock: 49118TOP264KG-TL Datasheet

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Key Parameters

Substitute Part Grouping Explanation

Substitution of the TOP242FN is determined by the following critical parameters:

Topology & Isolation: The substitute must maintain flyback topology with isolated output configuration. This ensures compatibility with existing transformer designs and circuit topologies.

Integrated Switch: The substitute must include an internal power switch to maintain the integrated controller architecture.

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

Switching Frequency: The substitute must support the 66kHz to 132kHz frequency range to maintain compatibility with transformer design and EMI filtering.

Fault Protection: The substitute must provide at minimum current limiting and over temperature protection. Additional protection features (over load, short circuit) represent functional enhancements.

Control Architecture: Frequency control capability must be present in the substitute.

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

Compliance: Both RoHS compliance and REACH unaffected status must be maintained.

The TOP264KG-TL qualifies as a substitute based on these criteria, though packaging and mounting type differ significantly.

Parameter Comparison

Engineering Selection Recommendations

Product Status Consideration: The TOP242FN is obsolete, while the TOP264KG-TL is active and in production. Selection of the TOP264KG-TL ensures long-term availability and supply chain continuity.

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

Electrical Compatibility: The TOP264KG-TL exceeds the TOP242FN in breakdown voltage (725V vs. 700V) and power rating (49W vs. 22W), providing design margin for the same application envelope. The switching frequency range remains compatible at 66kHz and 132kHz operation.

Protection Enhancement: The TOP264KG-TL includes over load and short circuit protection in addition to the current limiting, over temperature, and over voltage protection present in the TOP242FN. These additional protections do not create incompatibility; they represent functional enhancement.

Packaging and Mounting Impact: The TOP264KG-TL requires PCB redesign due to transition from through-hole TO-262-7 packaging to surface-mount 12-BESOP packaging. This represents the primary implementation consideration and necessitates circuit board layout modification.

Duty Cycle Difference: The TOP264KG-TL operates at 78% duty cycle compared to the TOP242FN at 66.5%. This difference reflects the newer generation design and requires transformer design verification to ensure compatibility with existing magnetic components.

Frequently Asked Questions (FAQ)

Q: Can the TOP264KG-TL directly replace the TOP242FN without PCB modification?

A: No. The TOP264KG-TL uses 12-BESOP surface-mount packaging with 11 leads and an exposed pad, while the TOP242FN uses TO-262-7 through-hole packaging with 6 leads. PCB redesign is required for footprint, trace routing, and thermal management.

Q: Are the switching frequencies compatible between these parts?

A: Yes. Both parts operate at 66kHz and 132kHz switching frequencies, maintaining compatibility with transformer design and EMI filtering requirements.

Q: Does the higher power rating of the TOP264KG-TL (49W vs. 22W) affect compatibility?

A: No. The higher power rating indicates increased capability and provides design margin. The part can operate at the 22W level required by the original TOP242FN application.

Q: What is the significance of the different duty cycles (66.5% vs. 78%)?

A: The duty cycle difference reflects design evolution between the TOPSwitch®-GX and TOPSwitch®-JX series. Transformer design must be verified to ensure the 78% duty cycle of the TOP264KG-TL is compatible with existing magnetic components designed for 66.5% operation.

Q: Are the additional fault protection features (over load, short circuit) in the TOP264KG-TL problematic?

A: No. Additional protection features enhance reliability and do not create incompatibility. They represent functional improvement over the TOP242FN.

Q: What is the impact of the higher breakdown voltage (725V vs. 700V)?

A: The higher breakdown voltage provides additional safety margin and is fully compatible with applications designed for 700V operation.

Q: Is the TOP264KG-TL available in the same through-hole package as the TOP242FN?

A: No. The TOP264KG-TL is available only in 12-BESOP surface-mount packaging. Through-hole alternatives would require evaluation of other Power Integrations TOPSwitch® series parts.

Q: What is the moisture sensitivity level difference between these parts?

A: The TOP242FN has MSL 1 (unlimited), while the TOP264KG-TL has MSL 3 (168 hours). The TOP264KG-TL requires controlled storage and handling conditions to prevent moisture absorption during the 168-hour window before soldering.

Q: Are both parts RoHS compliant?

A: Yes. Both the TOP242FN and TOP264KG-TL are RoHS compliant and REACH unaffected, satisfying regulatory requirements for equivalent applications.