TOP243YN Equivalent & Substitute Parts

Part Overview

The TOP243YN is an offline flyback converter IC manufactured by Power Integrations, part of the TOPSwitch®-GX series. This device integrates a high-voltage power switch with control circuitry for isolated flyback topology applications, delivering 45 W output power in a TO-220-7C package. The TOP243YN is classified as "Not For New Designs," indicating it is a legacy product. Alternative models within the TOPSwitch family are available to support ongoing production requirements and design flexibility across different power output specifications.

Substiute Parts

TOP243YN

Power IntegrationsIn Stock: 57383TOP243YN Datasheet

Current PartRFQ

TOP254YN

Power IntegrationsIn Stock: 4304TOP254YN Datasheet

SimilarRFQ

TOP242YN

Power IntegrationsIn Stock: 3740TOP242YN Datasheet

Parametric EquivalentRFQ

TOP244YN

Power IntegrationsIn Stock: 3712TOP244YN Datasheet

Parametric EquivalentRFQ

TOP245YN

Power IntegrationsIn Stock: 45423TOP245YN Datasheet

Parametric EquivalentRFQ

TOP246YN

Power IntegrationsIn Stock: 22608TOP246YN Datasheet

Parametric EquivalentRFQ

TOP247YN

Power IntegrationsIn Stock: 34266TOP247YN Datasheet

Parametric EquivalentRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitute parts for the TOP243YN are selected based on strict compatibility criteria within the Power Integrations TOPSwitch product family. The following parameters determine substitution eligibility:

Fixed Parameters (Must Match):

• Topology: Flyback
• Output Isolation: Isolated
• Voltage - Breakdown: 700V
• Package / Case: TO-220-7 Formed Leads, 6 Leads
• Mounting Type: Through Hole
• Operating Temperature Range: -40°C ~ 150°C (TJ)
• Fault Protection: Current Limiting, Over Temperature, Over Voltage
• RoHS Status: RoHS Compliant
• Moisture Sensitivity Level: 1 (Unlimited)

Variable Parameters (Determine Power Class):

• Power (Watts): Varies by model
• Series: TOPSwitch®-GX or TOPSwitch®-HX
• Frequency - Switching: 66kHz ~ 132kHz or fixed frequencies
• Duty Cycle: 66.5% or 78%
• Control Features: Frequency Control or absent

Substitute parts are grouped into two categories: TOPSwitch®-GX series (legacy, not for new designs) and TOPSwitch®-HX series (active status). Selection depends on required output power and design status requirements.

Parameter Comparison

Engineering Selection Recommendations

For Existing Production (Legacy Support): Designs currently using TOP243YN can continue with this part number. The TOP243YN maintains full compliance with RoHS and REACH regulations. Inventory of 57,300 units is available for ongoing production support.

For Power Output Adjustment Within TOPSwitch®-GX Series: If design modifications require different output power levels while maintaining legacy component status, select from TOP242YN (22 W), TOP244YN (65 W), TOP245YN (85 W), TOP246YN (125 W), or TOP247YN (165 W). All TOPSwitch®-GX variants share identical electrical and mechanical compatibility parameters with TOP243YN, differing only in rated power output.

For Active Product Status: The TOP254YN (TOPSwitch®-HX series) is the only active substitute available. This part delivers 62 W output power and operates at 78% duty cycle with fixed switching frequencies (66kHz or 132kHz). TOP254YN is suitable for new designs requiring similar functionality with active manufacturer support. This part is electrically and mechanically compatible with TOP243YN within the specified parameter constraints.

Compliance Considerations: All listed substitute parts maintain RoHS Compliance, REACH Unaffected status, and MSL 1 (Unlimited) moisture sensitivity rating, ensuring regulatory compatibility across all options.

Frequently Asked Questions (FAQ)

Q: Can TOP243YN be directly replaced with TOP254YN? A: Yes, within the specified electrical and mechanical parameters. Both devices share identical package (TO-220-7C), mounting type (Through Hole), voltage breakdown (700V), operating temperature range (-40°C ~ 150°C), and fault protection features. The TOP254YN delivers higher power output (62 W vs. 45 W) and operates at 78% duty cycle versus 66.5%. Verify that your application can accommodate the higher power rating and different duty cycle characteristics.

Q: What is the difference between TOPSwitch®-GX and TOPSwitch®-HX series? A: TOPSwitch®-GX series (TOP242YN through TOP247YN) are legacy products classified as "Not For New Designs." TOPSwitch®-HX series (TOP254YN) is active and supported for new designs. Both series share the same package, topology, and core protection features. The primary differences are duty cycle (66.5% vs. 78%), switching frequency control method, and product lifecycle status.

Q: Are all substitute parts pin-compatible with TOP243YN? A: Yes. All substitute parts use the TO-220-7 package with 6 formed leads, ensuring mechanical and pin compatibility. However, verify application-specific requirements for power output, duty cycle, and control characteristics before implementation.

Q: What inventory levels are available for each substitute? A: TOP245YN has the highest inventory (45,400 pcs), followed by TOP247YN (34,242 pcs) and TOP246YN (22,534 pcs). TOP243YN maintains 57,300 pcs. TOP254YN (active status) has 4,200 pcs available. TOP242YN and TOP244YN have lower inventory levels (3,633 and 3,675 pcs respectively).

Q: Can TOP243YN be used in new designs? A: No. TOP243YN is classified as "Not For New Designs." For new designs, use TOP254YN (TOPSwitch®-HX series, Active status) or consult Power Integrations for current-generation alternatives outside this product family.

Q: Do all substitute parts require identical PCB layout and transformer design? A: All substitute parts share identical electrical specifications for voltage breakdown, topology, isolation, and protection features. However, transformer design and PCB layout must be optimized for each part's specific power rating and duty cycle. Consult Power Integrations design guidelines for each model.