TOP223PN Equivalent & Substitute Parts

Part Overview

The TOP223PN is an offline switch IC manufactured by Power Integrations, designed for isolated power conversion applications. This device operates as a multi-topology converter supporting Boost, Buck, Flyback, and Forward topologies with a 25W power rating and 100kHz switching frequency. The TOP223PN is classified as "Not For New Designs," indicating it has been superseded in the product lifecycle. Finding equivalent and substitute parts is necessary for applications requiring continued support, design flexibility, or inventory optimization while maintaining electrical and mechanical compatibility.

Substiute Parts

TOP223PN

Power IntegrationsIn Stock: 19404TOP223PN Datasheet

Current PartRFQ

TOP243PN

Power IntegrationsIn Stock: 1602TOP243PN Datasheet

SimilarRFQ

TOP221PN

Power IntegrationsIn Stock: 17224TOP221PN Datasheet

Parametric EquivalentRFQ

TOP222PN

Power IntegrationsIn Stock: 17336TOP222PN Datasheet

Parametric EquivalentRFQ

TOP224PN

Power IntegrationsIn Stock: 18350TOP224PN Datasheet

Parametric EquivalentRFQ

FSQ0370RNA

onsemiIn Stock: 55170FSQ0370RNA Datasheet

SimilarRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitution of the TOP223PN is determined by strict alignment of the following critical parameters:

Primary Substitution Criteria:

• Package / Case: 8-DIP (0.300", 7.62mm) form factor
• Mounting Type: Through Hole
• Output Isolation: Isolated
• Internal Switch(s): Yes
• Voltage - Breakdown: 700V
• Operating Temperature Range: -40°C ~ 150°C (TJ)
• RoHS Status: RoHS Compliant

Secondary Compatibility Factors:

• Topology Support: Multi-topology capability (Boost, Buck, Flyback, Forward) or single-topology variants
• Power Rating: 25W nominal or adjacent power classes (9W, 15W, 30W)
• Switching Frequency: 100kHz or variable frequency operation
• Fault Protection: Current Limiting and Over Temperature minimum

Substitute parts are grouped into two categories:

Parametric Equivalents (TOPSwitch®-II Series): TOP221PN, TOP222PN, TOP224PN share identical electrical architecture, switching frequency, duty cycle, and package specifications. These differ only in power rating (9W, 15W, 30W respectively) and are direct functional substitutes for applications within their respective power envelopes.

Similar Alternatives (Different Series/Manufacturer): TOP243PN (TOPSwitch®-GX series) and FSQ0370RNA (onsemi FPS™ series) provide equivalent isolation, topology support, and package compatibility but operate at different switching frequencies and duty cycles. These require design verification for frequency-dependent circuit parameters.

Parameter Comparison

Engineering Selection Recommendations

For Direct Replacement (Same Series):

TOP221PN, TOP222PN, and TOP224PN are parametric equivalents within the TOPSwitch®-II series. Selection among these three depends on application power requirements:

• TOP221PN (9W): Applications requiring lower power envelope
• TOP222PN (15W): Mid-range power applications
• TOP224PN (30W): Higher power applications

All three maintain identical switching frequency (100kHz), duty cycle (67%), voltage breakdown (700V), and operating temperature range (-40°C ~ 150°C TJ) as the TOP223PN. These parts are interchangeable at the circuit topology level when power rating requirements are met. All are classified as "Not For New Designs" and carry RoHS Compliant certification.

For Alternative Series Selection:

TOP243PN (TOPSwitch®-GX series) provides equivalent power rating (25W) and isolation characteristics but operates at variable switching frequency (66kHz ~ 132kHz) with frequency control capability. This part is also "Not For New Designs" status. Selection requires verification that frequency variation does not impact transformer design, EMI filtering, or control loop stability.

FSQ0370RNA (onsemi FPS™ series) is the only "Active" product status option among all substitutes, providing long-term availability assurance. It delivers equivalent power (27W) and 100kHz switching frequency but operates at reduced duty cycle (60%) and lower maximum junction temperature (-40°C ~ 85°C TA). This part includes enhanced fault protection (Over Load, Over Voltage) and is ROHS3 Compliant. Selection requires verification that lower duty cycle and temperature rating align with application requirements.

Compliance Considerations:

All substitute parts maintain RoHS compliance and REACH unaffected status. FSQ0370RNA provides the highest compliance level (ROHS3) and active product status, making it the preferred choice for new applications or long-term production continuity.

Frequently Asked Questions (FAQ)

Q: Can TOP221PN, TOP222PN, or TOP224PN be used as direct pin-for-pin replacements for TOP223PN?

A: Yes, within power rating constraints. All three parts share identical 8-DIP package pinout, electrical architecture, switching frequency (100kHz), and duty cycle (67%). Selection depends on whether the application power requirement (9W, 15W, or 30W) matches the design specification. If the original design requires 25W operation, TOP224PN (30W) is the appropriate substitute.

Q: What is the key difference between TOP223PN and TOP243PN?

A: Both parts deliver 25W power and 700V breakdown voltage in 8-DIP packages. The primary difference is switching frequency operation: TOP223PN operates at fixed 100kHz, while TOP243PN operates at variable frequency (66kHz ~ 132kHz) with frequency control capability. TOP243PN is limited to Flyback topology, whereas TOP223PN supports multiple topologies (Boost, Buck, Flyback, Forward). Applications using Flyback topology may benefit from TOP243PN's frequency control feature, but circuit design must account for frequency variation.

Q: Why is FSQ0370RNA listed as a substitute if it has different operating temperature range?

A: FSQ0370RNA maintains all critical electrical parameters for isolation, topology, package, and mounting compatibility. The operating temperature difference (-40°C ~ 85°C TA versus -40°C ~ 150°C TJ) reflects measurement methodology (ambient versus junction temperature) and onsemi's product specification approach. Applications operating within -40°C ~ 85°C ambient conditions are fully compatible. Applications requiring junction temperatures above 85°C must verify thermal design margins with FSQ0370RNA.

Q: What is the significance of "Product Status: Not For New Designs" for TOP223PN and most substitutes?

A: This designation indicates the part has been superseded in the manufacturer's product lifecycle. Existing designs may continue using these parts, and inventory remains available. However, new product development should prioritize FSQ0370RNA (Active status) for long-term supply assurance and manufacturer support. For legacy system maintenance or repair, TOP223PN and its TOPSwitch®-II series equivalents remain viable.

Q: Are there any duty cycle differences that affect circuit design?

A: TOP223PN, TOP221PN, TOP222PN, and TOP224PN all operate at 67% duty cycle. TOP243PN operates at 66.5% (negligible difference). FSQ0370RNA operates at 60% duty cycle, which is a meaningful difference. Lower duty cycle affects transformer design, output filter requirements, and control loop response. Applications migrating to FSQ0370RNA must recalculate transformer turns ratio and filter component values based on the 60% duty cycle specification.

Q: Can these parts be used interchangeably in Flyback topology applications?

A: TOP223PN, TOP221PN, TOP222PN, and TOP224PN support Flyback topology among other topologies. TOP243PN and FSQ0370RNA are Flyback-only devices. For Flyback-specific applications, all six parts are compatible at the topology level. However, frequency differences (100kHz for TOP223PN/TOP221PN/TOP222PN/TOP224PN/FSQ0370RNA versus 66kHz ~ 132kHz for TOP243PN) require transformer and filter recalculation.

Q: What packaging considerations apply to these substitutes?

A: All substitute parts use 8-DIP (0.300", 7.62mm) through-hole packages. PCB footprints are mechanically identical. No layout modifications are required for physical substitution. Electrical performance differences (frequency, duty cycle, power rating) may require component value changes in the power stage and control circuits, but PCB routing and connector placement remain unchanged.

Q: Which substitute offers the best long-term availability?

A: FSQ0370RNA is the only part with "Active" product status, indicating ongoing manufacturer support and production commitment. All other substitutes are "Not For New Designs," meaning availability is limited to existing inventory. For applications requiring extended production runs or long-term support, FSQ0370RNA is the recommended choice despite minor parameter differences.