TOP221YN Equivalent & Substitute Parts Reference

Part Overview

The TOP221YN is an offline switching converter IC manufactured by Power Integrations, part of the TOPSwitch®-II series. This device integrates a high-voltage power switch with control circuitry for isolated power supply applications supporting Boost, Buck, Flyback, and Forward topologies. The TOP221YN is classified as "Not For New Designs," indicating it is a legacy product. For new applications or when TOP221YN availability becomes constrained, equivalent and substitute parts within the TOPSwitch®-II and TOPSwitch®-GX series provide functional alternatives with varying power ratings and packaging configurations.

Substiute Parts

TOP221YN

Power IntegrationsIn Stock: 5612TOP221YN Datasheet

Current PartRFQ

TOP242YN

Power IntegrationsIn Stock: 3740TOP242YN Datasheet

SimilarRFQ

TOP222YN

Power IntegrationsIn Stock: 56502TOP222YN Datasheet

Parametric EquivalentRFQ

TOP223YN

Power IntegrationsIn Stock: 25262TOP223YN Datasheet

Parametric EquivalentRFQ

TOP224YN

Power IntegrationsIn Stock: 39324TOP224YN Datasheet

Parametric EquivalentRFQ

TOP225YN

Power IntegrationsIn Stock: 8544TOP225YN Datasheet

Parametric EquivalentRFQ

TOP226YN

Power IntegrationsIn Stock: 9926TOP226YN Datasheet

Parametric EquivalentRFQ

TOP227YN

Power IntegrationsIn Stock: 10455TOP227YN Datasheet

Parametric EquivalentRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitution of the TOP221YN is determined by strict alignment of the following critical parameters:

Primary Substitution Criteria:

• Package / Case: TO-220-3 (Through Hole mounting)
• Voltage - Breakdown: 700V
• Topology Support: Boost, Buck, Flyback, Forward
• Frequency - Switching: 100kHz
• Duty Cycle: 67%
• Operating Temperature Range: -40°C ~ 150°C (TJ)
• Fault Protection: Current Limiting, Over Temperature minimum
• Output Isolation: Isolated
• RoHS Compliance: RoHS Compliant

Parametric Equivalent Parts (TOPSwitch®-II Series): Parts TOP222YN, TOP223YN, TOP224YN, TOP225YN, TOP226YN, and TOP227YN share identical electrical characteristics with TOP221YN except for power rating. These parts differ only in maximum power output (12W to 150W range) while maintaining the same package, topology support, switching frequency, voltage rating, and protection features. Selection among these parts is determined by the required power output of the application.

Similar Manufacturer Part (Different Series): The TOP242YN represents a different product series (TOPSwitch®-GX) with a different package (TO-220-7C) and topology limitation (Flyback only). This part is not a direct parametric equivalent due to package incompatibility and reduced topology support.

Parameter Comparison

Engineering Selection Recommendations

For Direct Replacement (Same Power Rating): The TOP221YN is specified for 12W applications. No other part in the provided substitute list matches this exact power rating. The TOP222YN (25W) is the next available option in the TOPSwitch®-II series with identical electrical and mechanical characteristics.

For Higher Power Applications: When application requirements exceed 12W, select from TOP222YN (25W), TOP223YN (50W), TOP224YN (75W), TOP225YN (100W), TOP226YN (125W), or TOP227YN (150W). All maintain identical package, topology support, switching frequency, voltage rating, and protection features. Selection is based solely on required power output.

Compliance Considerations: All substitute parts listed maintain RoHS Compliance and REACH Unaffected status, consistent with TOP221YN. All parts carry MSL 1 (Unlimited) moisture sensitivity rating. Through-hole mounting is preserved across all alternatives, ensuring PCB layout compatibility.

Product Status Impact: All listed parts, including TOP221YN, carry "Not For New Designs" status. This classification reflects the legacy nature of the TOPSwitch®-II series. For new design initiatives, evaluation of current-generation Power Integrations converter ICs is recommended, though this falls outside the scope of equivalent part selection for existing TOP221YN applications.

Frequently Asked Questions (FAQ)

Q: Can TOP222YN replace TOP221YN in an existing design? A: TOP222YN shares identical electrical characteristics, package, topology support, switching frequency, voltage rating, and protection features with TOP221YN. The difference is power rating: TOP222YN is rated for 25W versus TOP221YN at 12W. If the application requires only 12W, TOP222YN will operate within specification. PCB layout and thermal management remain compatible due to identical TO-220-3 packaging.

Q: What is the primary difference between TOP221YN and other TOPSwitch®-II parts? A: The TOPSwitch®-II series (TOP221YN through TOP227YN) differs only in maximum power output rating. All other parameters—package, topology support, switching frequency (100kHz), voltage rating (700V), duty cycle (67%), operating temperature range (-40°C to 150°C), and protection features—are identical across the series.

Q: Why is TOP242YN listed as a substitute but not recommended for direct replacement? A: TOP242YN belongs to the TOPSwitch®-GX series and differs in three critical parameters: (1) Package is TO-220-7C instead of TO-220-3, requiring different PCB footprint; (2) Topology support is limited to Flyback only, versus Boost, Buck, Flyback, and Forward in TOP221YN; (3) Switching frequency range is 66kHz–132kHz versus fixed 100kHz. These differences prevent direct substitution.

Q: Are all substitute parts RoHS compliant? A: Yes. All parts listed—TOP221YN, TOP222YN, TOP223YN, TOP224YN, TOP225YN, TOP226YN, and TOP227YN—are RoHS Compliant with MSL 1 (Unlimited) moisture sensitivity rating.

Q: What determines whether a part can substitute for TOP221YN? A: Substitution is determined by matching: (1) Package / Case (TO-220-3); (2) Voltage - Breakdown (700V); (3) Topology support (Boost, Buck, Flyback, Forward); (4) Switching frequency (100kHz); (5) Duty cycle (67%); (6) Operating temperature range (-40°C to 150°C); (7) Fault protection (minimum Current Limiting and Over Temperature); (8) Output isolation (Isolated); (9) RoHS compliance. Power rating is application-dependent and does not prevent substitution if the substitute rating meets or exceeds application requirements.

Q: Can TOP221YN be used in applications designed for higher-power parts like TOP227YN? A: No. TOP221YN is rated for 12W maximum. Using it in a 150W application (TOP227YN specification) would exceed device ratings and cause failure. Part selection must match or exceed application power requirements.

Q: Is thermal management different between TOP221YN and substitute parts? A: All parts use identical TO-220-3 packaging with the same thermal interface. Thermal performance differences relate to power dissipation at rated output, which varies with power rating. Higher-rated parts (TOP225YN, TOP226YN, TOP227YN) may dissipate more heat at full load, requiring appropriate thermal design consideration.