TOP243GN-TL Equivalent & Substitute Parts

Part Overview

The TOP243GN-TL is an offline switch 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 power supplies, operating at 66kHz to 132kHz switching frequency with 25W output power capability.

The TOP243GN-TL carries a "Not For New Designs" product status. This designation indicates the part remains available for existing applications and maintenance but is no longer recommended for new circuit development. Identifying equivalent and substitute parts becomes necessary for design flexibility, supply chain continuity, and future product iterations.

Key Parameters

Parameter	Value
Manufacturer	Power Integrations
Part Number	TOP243GN-TL
Series	TOPSwitch®-GX
Category	Power Management (PMIC)
Topology	Flyback
Output Isolation	Isolated
Voltage - Breakdown	700V
Frequency - Switching	66kHz ~ 132kHz
Power (Watts)	25W
Duty Cycle	66.5%
Fault Protection	Current Limiting, Over Temperature, Over Voltage
Control Features	Frequency Control
Package / Case	8-SMD (7 Leads), Gull Wing
Supplier Device Package	SMD-8B
Operating Temperature	-40°C ~ 150°C (TJ)
RoHS Status	RoHS Compliant
Moisture Sensitivity Level (MSL)	4 (72 Hours)

Substitute Part Grouping Explanation

Substitution eligibility for the TOP243GN-TL is determined by the following critical parameters:

Topology & Isolation: All substitute parts must maintain flyback topology with isolated output configuration.

Voltage Rating: Breakdown voltage of 700V is mandatory for compatibility with the same input voltage range and circuit protection requirements.

Switching Frequency Range: Operating frequency must fall within or overlap the 66kHz to 132kHz band to maintain circuit timing and EMI characteristics.

Package & Pinout: The 8-SMD (7 Leads) Gull Wing package (SMD-8B) is required for direct PCB compatibility without layout modifications.

Operating Temperature Range: The -40°C to 150°C junction temperature range must be maintained or exceeded.

Fault Protection Features: Current limiting, over-temperature, and over-voltage protection are baseline requirements.

Power Rating: Substitute parts must meet or exceed the 25W power handling capability, or be selected for lower-power applications where appropriate.

The substitute parts listed below satisfy these criteria within the Power Integrations TOPSwitch®-GX and TinySwitch®-III families.

Parameter Comparison

Parameter	TOP243GN-TL	TOP242GN-TL	TOP244GN-TL	TOP245GN-TL	TOP246GN-TL	TNY278GN-TL
Manufacturer	Power Integrations	Power Integrations	Power Integrations	Power Integrations	Power Integrations	Power Integrations
Series	TOPSwitch®-GX	TOPSwitch®-GX	TOPSwitch®-GX	TOPSwitch®-GX	TOPSwitch®-GX	TinySwitch®-III
Topology	Flyback	Flyback	Flyback	Flyback	Flyback	Flyback
Output Isolation	Isolated	Isolated	Isolated	Isolated	Isolated	Isolated
Voltage - Breakdown	700V	700V	700V	700V	700V	700V
Frequency - Switching	66kHz ~ 132kHz	66kHz ~ 132kHz	66kHz ~ 132kHz	66kHz ~ 132kHz	66kHz ~ 132kHz	132kHz
Power (Watts)	25W	15W	28W	30W	34W	28W
Duty Cycle	66.5%	66.5%	66.5%	66.5%	66.5%	65%
Fault Protection	Current Limiting, Over Temperature, Over Voltage	Current Limiting, Over Temperature, Over Voltage	Current Limiting, Over Temperature, Over Voltage	Current Limiting, Over Temperature, Over Voltage	Current Limiting, Over Temperature, Over Voltage	Current Limiting, Open Loop, Over Temperature, Over Voltage, Short Circuit
Control Features	Frequency Control	Frequency Control	Frequency Control	Frequency Control	Frequency Control	EN
Package / Case	8-SMD (7 Leads), Gull Wing	8-SMD (7 Leads), Gull Wing	8-SMD (7 Leads), Gull Wing	8-SMD (7 Leads), Gull Wing	8-SMD (7 Leads), Gull Wing	8-SMD (7 Leads), Gull Wing
Supplier Device Package	SMD-8B	SMD-8B	SMD-8B	SMD-8B	SMD-8B	SMD-8C
Operating Temperature	-40°C ~ 150°C (TJ)	-40°C ~ 150°C (TJ)	-40°C ~ 150°C (TJ)	-40°C ~ 150°C (TJ)	-40°C ~ 150°C (TJ)	-40°C ~ 150°C (TJ)
RoHS Status	RoHS Compliant	RoHS Compliant	RoHS Compliant	RoHS Compliant	RoHS Compliant	ROHS3 Compliant
Product Status	Not For New Designs	Not For New Designs	Not For New Designs	Not For New Designs	Not For New Designs	Active

Engineering Selection Recommendations

TOPSwitch®-GX Family Substitutes (TOP242GN-TL, TOP244GN-TL, TOP245GN-TL, TOP246GN-TL):

These parts share identical topology, voltage rating, frequency range, package configuration, and operating temperature specifications with the TOP243GN-TL. All are members of the TOPSwitch®-GX series and carry "Not For New Designs" status. Selection among these parts is determined by power rating requirements: TOP242GN-TL (15W) for lower-power applications, TOP244GN-TL (28W) for equivalent or slightly higher power, TOP245GN-TL (30W) for increased headroom, and TOP246GN-TL (34W) for maximum power capacity within the family.

TinySwitch®-III Alternative (TNY278GN-TL):

The TNY278GN-TL represents a cross-family substitute from the TinySwitch®-III series. It maintains the 700V breakdown voltage, isolated flyback topology, 8-SMD package, and -40°C to 150°C operating range. The TNY278GN-TL operates at a fixed 132kHz switching frequency (versus the TOP243GN-TL's variable 66kHz to 132kHz range) and provides enhanced fault protection including short-circuit detection and open-loop protection. The TNY278GN-TL carries "Active" product status, making it suitable for new designs. This part delivers 28W power capability and ROHS3 compliance.

Compliance Considerations:

All listed substitutes maintain RoHS compliance and REACH unaffected status. The TNY278GN-TL provides ROHS3 certification, representing the most current environmental compliance standard. Moisture sensitivity level remains consistent at MSL 4 across all parts.

Supply Chain Availability:

Current inventory levels vary: TOP243GN-TL (18,276 pcs), TOP244GN-TL (25,072 pcs), TOP242GN-TL (23,300 pcs), TNY278GN-TL (25,100 pcs), TOP245GN-TL (6,200 pcs), and TOP246GN-TL (3,700 pcs).

Frequently Asked Questions (FAQ)

Q: Can TOP242GN-TL replace TOP243GN-TL in existing designs?

A: TOP242GN-TL is a direct parametric equivalent with identical topology, voltage rating, frequency range, package, and operating temperature. The primary difference is power rating: TOP242GN-TL is rated for 15W versus TOP243GN-TL's 25W. Substitution is valid only if the application power requirement does not exceed 15W.

Q: What is the difference between TOP244GN-TL and TOP245GN-TL?

A: Both parts share identical electrical characteristics, topology, frequency range, and package specifications. The distinction is power rating: TOP244GN-TL is rated for 28W and TOP245GN-TL for 30W. Selection depends on the specific power budget of the application.

Q: Why is TNY278GN-TL listed as a substitute if it is from a different series?

A: TNY278GN-TL meets all critical substitution criteria: 700V breakdown voltage, isolated flyback topology, 8-SMD package, -40°C to 150°C operating range, and equivalent power capability (28W). Although from the TinySwitch®-III series rather than TOPSwitch®-GX, it provides functional equivalence. The TNY278GN-TL carries "Active" product status, offering an advantage for new designs.

Q: Are there pinout differences between TOP243GN-TL and its substitutes?

A: All listed substitutes use the 8-SMD (7 Leads) Gull Wing package configuration. While the TNY278GN-TL uses SMD-8C packaging versus SMD-8B for the TOPSwitch®-GX family, both are 8-lead SMD packages with identical lead pitch and gull-wing geometry, supporting direct PCB compatibility.

Q: What is the significance of "Not For New Designs" status?

A: This designation indicates the part is in mature/legacy phase. Existing inventory remains available for maintenance and support of fielded products. For new circuit development, the TNY278GN-TL with "Active" status is the recommended choice among the listed substitutes.

Q: How do switching frequency differences affect substitution?

A: TOP243GN-TL operates across a 66kHz to 132kHz range with frequency control capability. TOP244GN-TL, TOP245GN-TL, and TOP246GN-TL share this same frequency range. TNY278GN-TL operates at fixed 132kHz. Frequency differences impact transformer design, EMI characteristics, and component selection. Substitution requires verification that the target frequency range is compatible with the power supply design.

Q: What additional fault protection does TNY278GN-TL provide?

A: TNY278GN-TL includes short-circuit and open-loop protection in addition to the current limiting, over-temperature, and over-voltage protection common to all listed parts. These additional protections enhance system robustness in fault conditions.

Q: Are all substitutes RoHS compliant?

A: Yes. TOP243GN-TL and the TOPSwitch®-GX family (TOP242GN-TL, TOP244GN-TL, TOP245GN-TL, TOP246GN-TL) are RoHS Compliant. TNY278GN-TL is ROHS3 Compliant, representing the current environmental standard. All parts are REACH Unaffected.

Request Quote (Ships tomorrow)

Part Number

Quantity

Company

Contact Name

E-mail

Message