TOP243Y Equivalent & Substitute Parts

Part Overview

The TOP243Y is an offline flyback converter IC from Power Integrations' TOPSwitch®-GX series, designed for isolated power supply applications. This component integrates a high-voltage switch with control circuitry in a TO-220-7 package, delivering 45W output power with integrated fault protection.

The TOP243Y is classified as Obsolete. Locating equivalent substitute parts is necessary for ongoing production support, design updates, and inventory replenishment where original stock becomes unavailable.

Substiute Parts

TOP243Y

Power IntegrationsIn Stock: 816TOP243Y Datasheet

Current PartRFQ

TOP243YN

Power IntegrationsIn Stock: 57383TOP243YN Datasheet

DirectRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitution eligibility for the TOP243Y is determined by strict alignment with the following critical parameters:

Mandatory Matching Parameters:

• Topology: Flyback
• Output Isolation: Isolated
• Package / Case: TO-220-7 Formed Leads, 6 Leads
• Mounting Type: Through Hole
• Voltage - Breakdown: 700V
• Power (Watts): 45 W
• Frequency - Switching: 66kHz ~ 132kHz
• Duty Cycle: 66.5%
• Fault Protection: Current Limiting, Over Temperature, Over Voltage
• Control Features: Frequency Control
• Operating Temperature: -40°C ~ 150°C (TJ)

The TOP243YN is identified as a direct substitute. Both parts share identical electrical specifications, topology, and mechanical packaging. The primary difference is packaging format (Tube vs. standard) and product status classification.

Parameter Comparison

Engineering Selection Recommendations

For Existing Designs (Maintenance & Repair): The TOP243YN serves as the direct functional equivalent to TOP243Y. Both components are electrically and mechanically identical across all critical parameters. The TOP243YN is available in higher inventory quantities (57,300 pcs vs. 772 pcs) and carries RoHS Compliant certification, making it suitable for replacement in existing production runs where component-level substitution is required.

For New Design Initiatives: The TOP243YN carries a "Not For New Designs" status classification. This designation indicates that Power Integrations does not recommend this part for new product development. Designs requiring flyback topology with 45W output and 700V breakdown voltage should evaluate current-generation alternatives from the TOPSwitch®-GX series as specified in the substitute list (TOP245YN, TOP246YN, TOP247YN, TOP254YN, TOP242YN).

Compliance Considerations: The TOP243Y is RoHS non-compliant. The TOP243YN achieves RoHS Compliance. For applications subject to RoHS regulatory requirements, the TOP243YN is the appropriate selection. Both parts maintain REACH Unaffected status and EAR99 export classification.

Frequently Asked Questions (FAQ)

Q: Can TOP243YN be used as a direct replacement for TOP243Y in existing circuit boards?

A: Yes. The TOP243YN is electrically and mechanically identical to TOP243Y. Pin configuration, electrical characteristics, thermal performance, and package dimensions are equivalent. No circuit modifications are required for component substitution.

Q: What is the difference between TOP243Y and TOP243YN?

A: The primary differences are: (1) Packaging format—TOP243Y uses standard packaging while TOP243YN uses Tube packaging; (2) Product status—TOP243Y is Obsolete while TOP243YN is Not For New Designs; (3) RoHS compliance—TOP243Y is non-compliant while TOP243YN is compliant. Electrical and mechanical specifications are identical.

Q: Why is TOP243YN classified as "Not For New Designs"?

A: This classification indicates that Power Integrations has transitioned this part to end-of-life status and recommends newer alternatives for new product development. However, TOP243YN remains suitable for maintenance, repair, and replacement in existing designs.

Q: Are there newer alternatives to TOP243Y/TOP243YN for new designs?

A: Yes. Power Integrations offers alternative parts within the TOPSwitch®-GX series: TOP245YN, TOP246YN, TOP247YN, TOP254YN, and TOP242YN. These alternatives should be evaluated for new design initiatives requiring similar functionality.

Q: What is the inventory status for TOP243YN?

A: TOP243YN has 57,300 pcs in stock (New Original), providing significantly higher availability compared to TOP243Y (772 pcs). This makes TOP243YN the practical choice for ongoing production support.

Q: Does switching from TOP243Y to TOP243YN require PCB layout changes?

A: No. Both parts use identical TO-220-7 package geometry with 6 leads and through-hole mounting. PCB footprints, lead spacing, and thermal pad requirements are equivalent. No layout modifications are necessary.

Q: What is the operating temperature range for both parts?

A: Both TOP243Y and TOP243YN operate across -40°C to 150°C junction temperature (TJ), supporting industrial and consumer applications across extended temperature ranges.