TOP246PN Equivalent & Substitute Parts

Part Overview

The TOP246PN is an offline flyback converter IC from Power Integrations' TOPSwitch®-GX series, designed for isolated power supply applications. This 8-DIP package device integrates a high-voltage switch with comprehensive fault protection, operating at 66kHz to 132kHz switching frequency with 34W power capability. The TOP246PN carries a "Not For New Designs" product status, making identification of equivalent and substitute parts essential for ongoing production support and design alternatives.

Key Parameters

Parameter	Value
Manufacturer Part Number	TOP246PN
Manufacturer	Power Integrations
Series	TOPSwitch®-GX
Category	Power Management (PMIC)
Topology	Flyback
Voltage - Breakdown	700V
Frequency - Switching	66kHz ~ 132kHz
Power (Watts)	34 W
Duty Cycle	66.5%
Package / Case	8-DIP (0.300", 7.62mm), 7 Leads
Mounting Type	Through Hole
Operating Temperature	-40°C ~ 150°C (TJ)
Fault Protection	Current Limiting, Over Temperature, Over Voltage
Output Isolation	Isolated
RoHS Status	RoHS Compliant
Product Status	Not For New Designs

Substitute Part Grouping Explanation

Substitute parts for the TOP246PN are classified based on the following critical parameters that determine functional compatibility:

Primary Substitution Criteria:

Topology: Flyback converter architecture
Voltage - Breakdown: 700V rating
Package / Case: 8-DIP (0.300", 7.62mm) form factor
Output Isolation: Isolated configuration
Internal Switch(s): Integrated high-voltage switch
Mounting Type: Through Hole compatibility
Operating Temperature Range: -40°C minimum to 150°C maximum

Substitution Categories:

Category 1: Parametric Equivalents (TOPSwitch®-GX Series) Parts TOP242PN, TOP243PN, TOP244PN, and TOP245PN share identical electrical architecture, switching frequency range (66kHz ~ 132kHz), duty cycle (66.5%), package type (8-PDIP-B), and fault protection features. These differ only in power rating (15W, 25W, 28W, and 30W respectively) and are suitable for applications where the 34W rating of TOP246PN exceeds system requirements.

Category 2: Similar Manufacturer Alternative (TOPSwitch®-HX Series) The TOP256PN represents an alternative from Power Integrations' newer TOPSwitch®-HX series. While maintaining 700V breakdown voltage, 8-DIP package, and isolated topology, it operates at fixed 66kHz frequency with 78% duty cycle and carries Active product status. The 8-PDIP-C package variant differs from TOP246PN's 8-PDIP-B.

Category 3: Cross-Manufacturer Alternative The NCP1079BAP130G from onsemi provides equivalent isolated flyback topology with 700V breakdown voltage in 8-DIP package. It operates at 130kHz fixed frequency with 68% duty cycle and 41W power capability. This part includes additional fault protection (Short Circuit, Over Power) and carries Active product status with ROHS3 compliance.

Parameter Comparison

Parameter	TOP246PN	TOP242PN	TOP243PN	TOP244PN	TOP245PN	TOP256PN	NCP1079BAP130G
Manufacturer	Power Integrations	Power Integrations	Power Integrations	Power Integrations	Power Integrations	Power Integrations	onsemi
Series	TOPSwitch®-GX	TOPSwitch®-GX	TOPSwitch®-GX	TOPSwitch®-GX	TOPSwitch®-GX	TOPSwitch®-HX	-
Topology	Flyback	Flyback	Flyback	Flyback	Flyback	Flyback	Flyback
Voltage - Breakdown	700V	700V	700V	700V	700V	700V	700V
Frequency - Switching	66kHz ~ 132kHz	66kHz ~ 132kHz	66kHz ~ 132kHz	66kHz ~ 132kHz	66kHz ~ 132kHz	66kHz	130kHz
Power (Watts)	34 W	15 W	25 W	28 W	30 W	34 W	41 W
Duty Cycle	66.5%	66.5%	66.5%	66.5%	66.5%	78%	68%
Package / Case	8-DIP (0.300", 7.62mm)	8-DIP (0.300", 7.62mm)	8-DIP (0.300", 7.62mm)	8-DIP (0.300", 7.62mm)	8-DIP (0.300", 7.62mm)	8-DIP (0.300", 7.62mm)	8-DIP (0.300", 7.62mm)
Supplier Device Package	8-PDIP-B	8-PDIP-B	8-PDIP-B	8-PDIP-B	8-PDIP-B	8-PDIP-C	8-PDIP
Mounting Type	Through Hole	Through Hole	Through Hole	Through Hole	Through Hole	Through Hole	Through Hole
Operating Temperature	-40°C ~ 150°C	-40°C ~ 150°C	-40°C ~ 150°C	-40°C ~ 150°C	-40°C ~ 150°C	-40°C ~ 150°C	-40°C ~ 125°C
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, Over Temperature, Over Voltage	Current Limiting, Over Power, Over Temperature, Over Voltage, Short Circuit
Output Isolation	Isolated	Isolated	Isolated	Isolated	Isolated	Isolated	Isolated
RoHS Status	RoHS Compliant	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	Active

Engineering Selection Recommendations

For Direct Replacement (Same Power Rating): The TOP256PN from Power Integrations' TOPSwitch®-HX series provides the closest functional replacement with identical 34W power rating and 700V breakdown voltage. This part carries Active product status, ensuring long-term availability and support. The fixed 66kHz switching frequency and 78% duty cycle differ from TOP246PN's variable frequency range, requiring transformer design verification. The 8-PDIP-C package variant maintains through-hole compatibility with existing PCB layouts.

For Power-Scaled Applications: When system power requirements are lower than 34W, the TOPSwitch®-GX series alternatives (TOP242PN at 15W, TOP243PN at 25W, TOP244PN at 28W, TOP245PN at 30W) provide direct substitutes with identical switching frequency range, duty cycle, and package type. All maintain "Not For New Designs" status consistent with TOP246PN.

For New Design Initiatives: The NCP1079BAP130G from onsemi represents the recommended choice for new designs requiring isolated flyback topology. This part carries Active product status with ROHS3 compliance, ensuring regulatory alignment and supply chain continuity. The 41W power capability exceeds TOP246PN specifications, and the fixed 130kHz switching frequency with enhanced fault protection (including Short Circuit and Over Power detection) provides improved system robustness. Operating temperature range extends to -40°C minimum but limits to 125°C maximum, requiring thermal analysis for high-temperature applications.

Compliance Considerations: All substitute parts maintain RoHS compliance and REACH unaffected status. The NCP1079BAP130G provides ROHS3 certification for enhanced regulatory alignment. All parts carry EAR99 ECCN classification and identical HTSUS code (8542.39.0001).

Frequently Asked Questions (FAQ)

Q: Can TOP242PN, TOP243PN, TOP244PN, or TOP245PN directly replace TOP246PN?

A: These parts share identical electrical architecture, switching frequency range (66kHz ~ 132kHz), duty cycle (66.5%), package type (8-PDIP-B), and fault protection features. Direct substitution is possible only when system power requirements do not exceed the respective ratings (15W, 25W, 28W, 30W). Transformer design and output power stage must be verified for lower-power variants.

Q: What are the key differences between TOP256PN and TOP246PN?

A: Both parts deliver 34W power with 700V breakdown voltage in 8-DIP through-hole packages. TOP256PN operates at fixed 66kHz frequency with 78% duty cycle, compared to TOP246PN's variable 66kHz ~ 132kHz range with 66.5% duty cycle. TOP256PN uses 8-PDIP-C package variant versus TOP246PN's 8-PDIP-B. TOP256PN carries Active product status. Transformer design requires adjustment for the fixed frequency and altered duty cycle.

Q: Is NCP1079BAP130G suitable for direct replacement?

A: NCP1079BAP130G provides equivalent isolated flyback topology with 700V breakdown voltage and 8-DIP through-hole package. However, it operates at fixed 130kHz frequency with 68% duty cycle and 41W power capability. The different switching frequency and duty cycle require transformer redesign. This part is recommended for new designs rather than direct replacement of legacy TOP246PN applications.

Q: What is the impact of switching frequency differences on circuit design?

A: Switching frequency directly determines transformer core size, winding inductance, and output filter component values. TOP246PN's variable 66kHz ~ 132kHz range allows frequency control for load regulation. TOP256PN's fixed 66kHz and NCP1079BAP130G's fixed 130kHz require fixed transformer designs. Frequency changes affect EMI characteristics and thermal performance. Transformer and filter redesign is necessary when substituting parts with different frequency specifications.

Q: Are all substitute parts available in the same package footprint?

A: All substitute parts use 8-DIP (0.300", 7.62mm) through-hole packages with 7 leads, ensuring PCB footprint compatibility. However, package variants differ: TOP246PN and TOPSwitch®-GX series use 8-PDIP-B, TOP256PN uses 8-PDIP-C, and NCP1079BAP130G uses standard 8-PDIP. These variants maintain identical lead spacing and through-hole positioning, allowing direct PCB mounting without layout modification.

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

A: This designation indicates that TOP246PN, TOP242PN, TOP243PN, TOP244PN, and TOP245PN are mature products no longer recommended for new circuit designs. Power Integrations continues to support existing applications but directs new designs toward active alternatives. TOP256PN (TOPSwitch®-HX series) and NCP1079BAP130G (onsemi) carry Active status, making them preferred choices for new development initiatives.

Q: How do fault protection features compare across substitute parts?

A: TOP246PN and all TOPSwitch®-GX variants provide Current Limiting, Over Temperature, and Over Voltage protection. NCP1079BAP130G adds Over Power and Short Circuit protection, offering enhanced system robustness. The additional protection features in NCP1079BAP130G provide superior fault response but do not affect direct substitution compatibility for applications where these features are not required.

Q: What are the operating temperature implications for substitution?

A: TOP246PN and all Power Integrations substitutes operate from -40°C to 150°C junction temperature. NCP1079BAP130G limits maximum junction temperature to 125°C. For applications requiring operation above 125°C, NCP1079BAP130G is unsuitable. Power Integrations alternatives maintain the full -40°C to 150°C range, making them necessary for high-temperature applications.

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