TOP221P Equivalent & Substitute Parts Reference

Part Overview

The TOP221P is an offline switch IC from Power Integrations' TOPSwitch®-II series, designed for isolated power conversion applications. This component functions as a controller and integrated power switch for boost, buck, flyback, and forward converter topologies operating at 100kHz switching frequency with 9W power capability.

The TOP221P carries an Obsolete product status. Locating equivalent substitute parts is necessary for design continuity, repair operations, and legacy system maintenance. The substitute parts listed maintain electrical and mechanical compatibility while offering improved availability and updated compliance certifications.

Key Parameters

Parameter	Value
Manufacturer	Power Integrations
Series	TOPSwitch®-II
Package / Case	8-DIP (0.300", 7.62mm)
Mounting Type	Through Hole
Voltage - Breakdown	700V
Topology	Boost, Buck, Flyback, Forward
Frequency - Switching	100kHz
Duty Cycle	67%
Output Isolation	Isolated
Internal Switch(s)	Yes
Fault Protection	Current Limiting, Over Temperature
Operating Temperature	-40°C ~ 150°C (TJ)

Substitute Part Grouping Explanation

Substitution eligibility for the TOP221P is determined by strict adherence to the following parameters:

Fixed Compatibility Parameters:

Manufacturer: Power Integrations
Series: TOPSwitch®-II
Package / Case: 8-DIP (0.300", 7.62mm)
Mounting Type: Through Hole
Voltage - Breakdown: 700V
Topology: Boost, Buck, Flyback, Forward
Frequency - Switching: 100kHz
Duty Cycle: 67%
Output Isolation: Isolated
Internal Switch(s): Yes
Fault Protection: Current Limiting, Over Temperature
Operating Temperature: -40°C ~ 150°C (TJ)

Variable Parameter (Allows Substitution):

Power (Watts): The TOP221P operates at 9W. Substitute parts with equal or higher power ratings (TOP221PN at 9W, TOP222PN at 15W, TOP223PN at 25W, TOP224PN at 30W) are electrically compatible for applications requiring the TOP221P's power level or less.

All substitute parts maintain identical electrical characteristics, pinout compatibility, and thermal specifications. Differences in power rating reflect design variants within the same product family, allowing upward substitution for applications with higher power requirements.

Parameter Comparison

Part Number	Manufacturer	Power (Watts)	Package	Voltage - Breakdown	Frequency - Switching	Product Status	RoHS Status	Inventory (Pcs)
TOP221P	Power Integrations	9 W	8-DIP	700V	100kHz	Obsolete	RoHS non-compliant	1264
TOP221PN	Power Integrations	9 W	8-DIP	700V	100kHz	Not For New Designs	RoHS Compliant	17200
TOP222PN	Power Integrations	15 W	8-DIP	700V	100kHz	Not For New Designs	RoHS Compliant	17300
TOP223PN	Power Integrations	25 W	8-DIP	700V	100kHz	Not For New Designs	RoHS Compliant	19357
TOP224PN	Power Integrations	30 W	8-DIP	700V	100kHz	Not For New Designs	RoHS Compliant	18245

Engineering Selection Recommendations

For Direct Replacement (Identical Power Rating): TOP221PN is the direct equivalent to TOP221P, maintaining the 9W power specification. TOP221PN offers improved availability (17200 units in stock versus 1264 for TOP221P) and RoHS compliance certification, making it the preferred choice for legacy system repairs and component replenishment.

For Applications Requiring Higher Power Capacity: TOP222PN (15W), TOP223PN (25W), and TOP224PN (30W) provide upward substitution options. These parts maintain all electrical and mechanical compatibility parameters while delivering increased power handling capability. Selection depends on application power requirements.

Compliance Considerations: All substitute parts (TOP221PN, TOP222PN, TOP223PN, TOP224PN) carry RoHS Compliant certification, whereas the original TOP221P is RoHS non-compliant. This distinction is relevant for applications subject to RoHS regulatory requirements. All parts maintain REACH Unaffected status and EAR99 export classification.

Product Status Impact: The TOP221P is classified as Obsolete. All substitute parts carry "Not For New Designs" status, indicating limited long-term availability. For new product development, evaluation of current-generation Power Integrations offline switch solutions is recommended.

Frequently Asked Questions (FAQ)

Q: Can TOP222PN, TOP223PN, or TOP224PN be used as direct replacements for TOP221P?

A: Yes, with power rating considerations. All four substitute parts share identical package, pinout, voltage rating, switching frequency, topology support, and operating temperature range. TOP222PN, TOP223PN, and TOP224PN have higher power ratings (15W, 25W, 30W respectively) than TOP221P (9W). They are electrically compatible for applications operating at or below the TOP221P's 9W specification. Applications requiring higher power output can utilize the higher-rated variants.

Q: What is the difference between TOP221P and TOP221PN?

A: TOP221P and TOP221PN are functionally identical with 9W power rating. The primary differences are packaging (TOP221P in standard packaging, TOP221PN in Tube packaging), product status (Obsolete versus Not For New Designs), and RoHS compliance (non-compliant versus compliant). TOP221PN offers significantly higher inventory availability.

Q: Are all substitute parts pin-compatible with TOP221P?

A: Yes. All substitute parts use the 8-DIP (0.300", 7.62mm) package with identical pinout. Through-hole mounting compatibility is maintained across all variants.

Q: Which substitute part should be selected for new designs?

A: All listed substitute parts carry "Not For New Designs" status. For new product development, current-generation Power Integrations offline switch ICs should be evaluated. For legacy system maintenance and repair, TOP221PN is the recommended direct equivalent.

Q: What is the inventory status of substitute parts?

A: TOP221PN, TOP222PN, TOP223PN, and TOP224PN all maintain substantial inventory levels (17200, 17300, 19357, and 18245 units respectively), significantly exceeding TOP221P availability (1264 units).

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