TOP226YN Equivalent & Substitute Parts Reference

Part Overview

The TOP226YN 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 TOP226YN is classified as "Not For New Designs," indicating it is a legacy product. For new development projects or when TOP226YN inventory becomes unavailable, equivalent substitute parts from the TOPSwitch®-II series provide direct functional replacement with identical electrical and mechanical specifications.

Key Parameters

Parameter	TOP226YN Specification
Manufacturer	Power Integrations
Series	TOPSwitch®-II
Package / Case	TO-220-3
Mounting Type	Through Hole
Voltage - Breakdown	700V
Topology Support	Boost, Buck, Flyback, Forward
Frequency - Switching	100kHz
Power (Watts)	125 W
Duty Cycle	67%
Fault Protection	Current Limiting, Over Temperature
Output Isolation	Isolated
Operating Temperature	-40°C ~ 150°C (TJ)
RoHS Status	RoHS Compliant
Moisture Sensitivity Level (MSL)	1 (Unlimited)

Substitute Part Grouping Explanation

Substitute parts for the TOP226YN are selected based on strict electrical and mechanical compatibility criteria. The primary substitution logic is based on the following parameters:

Critical Matching Parameters:

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

Variable Parameter (Power Rating): The power rating in watts is the primary differentiator among TOPSwitch®-II devices. Substitute parts are available in the following power ratings: 12W (TOP221YN), 25W (TOP222YN), 50W (TOP223YN), 75W (TOP224YN), 100W (TOP225YN), 125W (TOP226YN), and 150W (TOP227YN). Selection of a substitute part depends on the actual power requirement of the application circuit.

All substitute parts maintain identical electrical characteristics, package configuration, and thermal specifications, ensuring direct pin-compatible replacement when power rating requirements are met.

Parameter Comparison

Part Number	Power (W)	Package	Topology	Frequency (kHz)	Voltage Breakdown (V)	Duty Cycle (%)	Temp Range (°C)	Inventory (Pcs)
TOP221YN	12	TO-220-3	Boost, Buck, Flyback, Forward	100	700	67	-40 ~ 150	5,525
TOP222YN	25	TO-220-3	Boost, Buck, Flyback, Forward	100	700	67	-40 ~ 150	56,400
TOP223YN	50	TO-220-3	Boost, Buck, Flyback, Forward	100	700	67	-40 ~ 150	25,200
TOP224YN	75	TO-220-3	Boost, Buck, Flyback, Forward	100	700	67	-40 ~ 150	39,300
TOP225YN	100	TO-220-3	Boost, Buck, Flyback, Forward	100	700	67	-40 ~ 150	8,475
TOP226YN	125	TO-220-3	Boost, Buck, Flyback, Forward	100	700	67	-40 ~ 150	9,842
TOP227YN	150	TO-220-3	Boost, Buck, Flyback, Forward	100	700	67	-40 ~ 150	10,400

Engineering Selection Recommendations

For Direct Replacement (125W Applications): The TOP226YN is the primary component for 125W power supply designs. When TOP226YN stock is depleted or unavailable, no direct equivalent exists within the TOPSwitch®-II series at the identical 125W rating. In such cases, design modification or alternative series evaluation is required.

For Uprating (Higher Power Requirements): The TOP227YN (150W) provides the next power level above TOP226YN. This device is suitable for applications where the circuit design can accommodate the higher power rating without modification. All electrical and mechanical parameters remain identical to TOP226YN.

For Downrating (Lower Power Requirements): If the application circuit can operate at reduced power levels, TOP225YN (100W), TOP224YN (75W), TOP223YN (50W), TOP222YN (25W), or TOP221YN (12W) are available as substitutes. These parts are pin-compatible and require no circuit redesign when power derating is acceptable.

Compliance and Status: All substitute parts maintain RoHS Compliance, REACH Unaffected status, and MSL Level 1 (Unlimited) moisture sensitivity rating, identical to TOP226YN. All parts are classified as "Not For New Designs," indicating legacy product status across the entire TOPSwitch®-II series.

Frequently Asked Questions (FAQ)

Q: Can TOP227YN (150W) be used as a direct replacement for TOP226YN (125W)?

A: TOP227YN is pin-compatible and electrically compatible with TOP226YN. However, it is rated for 150W output power. Use TOP227YN only if the application circuit design can accommodate or tolerate the higher power rating. No circuit modification is required for pin compatibility.

Q: Can TOP225YN (100W) be used in a TOP226YN (125W) application?

A: TOP225YN is pin-compatible with TOP226YN but is rated for 100W maximum output power. It cannot be used in applications requiring 125W output power, as this would exceed the device's power rating and cause thermal stress or failure.

Q: Are all TOPSwitch®-II devices in the TOP22xYN series interchangeable?

A: All TOP22xYN devices (TOP221YN through TOP227YN) share identical electrical characteristics, package configuration (TO-220-3), topology support, switching frequency, and thermal specifications. They differ only in power rating. Interchangeability depends on whether the application power requirement matches or is lower than the substitute part's rating.

Q: What is the difference between TOP226YN and TOP246YN?

A: TOP246YN belongs to the TOPSwitch®-GX series and uses a different package (TO-220-7C with 6 leads) compared to TOP226YN (TO-220-3 with 3 leads). TOP246YN supports only Flyback topology, whereas TOP226YN supports Boost, Buck, Flyback, and Forward topologies. These devices are not pin-compatible and require circuit redesign for substitution.

Q: Are there any control feature differences among TOP22xYN substitutes?

A: All TOP22xYN devices in the TOPSwitch®-II series have identical control features (listed as "-" in specifications), indicating no programmable or external control features. All devices operate with fixed internal control parameters.

Q: What is the significance of the 67% duty cycle specification?

A: The 67% duty cycle is a fixed internal characteristic of all TOP22xYN devices, indicating the maximum on-time ratio of the internal power switch. This parameter is identical across all substitute parts and does not vary by power rating.

Q: Can TOP226YN be used in applications requiring the TO-220-7 package?

A: No. TOP226YN uses TO-220-3 package with 3 leads. Applications requiring TO-220-7 package (such as TOP246YN) require different PCB layout and cannot use TOP226YN without complete circuit redesign.

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