TOP257EN Equivalent & Substitute Parts Reference

Part Overview

The TOP257EN is an offline flyback converter IC from Power Integrations' TOPSwitch®-HX series, designed for isolated power management applications. This 7-pin eSIP package device operates at 66kHz or 132kHz switching frequency with a 700V breakdown voltage rating and delivers 157W output power. The component integrates an internal switch with comprehensive fault protection including current limiting, over-temperature, and over-voltage protection. Product status is Active with full RoHS compliance and unlimited moisture sensitivity rating (MSL 1).

Substitute parts are necessary when the original TOP257EN is unavailable, when inventory constraints require alternative sourcing, or when application power requirements differ from the 157W specification while maintaining the same topology, package, and electrical characteristics.

Key Parameters

Parameter	Value	Significance for Substitution
Manufacturer	Power Integrations	Ensures consistent design and quality standards across TOPSwitch®-HX series
Series	TOPSwitch®-HX	Defines the IC architecture and control methodology
Topology	Flyback	Determines circuit configuration and transformer requirements
Output Isolation	Isolated	Specifies galvanic isolation capability for safety-critical applications
Voltage - Breakdown	700V	Maximum input voltage rating; critical for component reliability
Frequency - Switching	66kHz, 132kHz	Determines transformer core size and external component selection
Package / Case	7-SSIP, 6 Leads, Exposed Pad, Formed Leads	Physical compatibility with PCB layout and thermal management
Supplier Device Package	eSIP-7C	Ensures mechanical and electrical compatibility with existing designs
Mounting Type	Through Hole	Determines assembly process and PCB design requirements
Duty Cycle	78%	Defines maximum on-time and affects power delivery capability
Power (Watts)	157W	Application-dependent; varies across substitute parts
Fault Protection	Current Limiting, Over Temperature, Over Voltage	Ensures consistent protection features across substitutes
Operating Temperature	-40°C ~ 150°C (TJ)	Defines thermal operating range for system design
RoHS Status	RoHS Compliant	Regulatory compliance requirement

Substitute Part Grouping Explanation

Substitution within the TOPSwitch®-HX series is determined by strict adherence to the following parameters:

Fixed Parameters (Must Match for Substitution):

Manufacturer: Power Integrations
Series: TOPSwitch®-HX
Topology: Flyback
Output Isolation: Isolated
Voltage - Breakdown: 700V
Frequency - Switching: 66kHz, 132kHz
Package / Case: 7-SSIP, 6 Leads, Exposed Pad, Formed Leads
Supplier Device Package: eSIP-7C
Mounting Type: Through Hole
Duty Cycle: 78%
Fault Protection: Current Limiting, Over Temperature, Over Voltage
Operating Temperature: -40°C ~ 150°C (TJ)
RoHS Status: RoHS Compliant
Moisture Sensitivity Level: 1 (Unlimited)

Variable Parameter (Differs Across Substitutes):

Power (Watts): Ranges from 25W to 275W depending on specific part number

All substitute parts listed maintain identical electrical characteristics, protection features, and package specifications. The primary differentiator is the maximum power rating, which must be selected based on application requirements. Parts with higher power ratings can be used in applications requiring lower power, provided thermal management and PCB layout accommodate the device.

Parameter Comparison

Part Number	Manufacturer	Series	Topology	Voltage Breakdown	Switching Frequency	Power Rating (W)	Package	Duty Cycle	Operating Temp (°C)	Inventory (Pcs)
TOP257EN	Power Integrations	TOPSwitch®-HX	Flyback	700V	66kHz, 132kHz	157	7-SSIP eSIP-7C	78%	-40 to 150	1436
TOP253EN	Power Integrations	TOPSwitch®-HX	Flyback	700V	66kHz, 132kHz	25	7-SSIP eSIP-7C	78%	-40 to 150	1177
TOP254EG	Power Integrations	TOPSwitch®-HX	Flyback	700V	66kHz, 132kHz	62	7-SSIP eSIP-7C	78%	-40 to 150	16400
TOP254EN	Power Integrations	TOPSwitch®-HX	Flyback	700V	66kHz, 132kHz	62	7-SSIP eSIP-7C	78%	-40 to 150	3834
TOP255EN	Power Integrations	TOPSwitch®-HX	Flyback	700V	66kHz, 132kHz	81	7-SSIP eSIP-7C	78%	-40 to 150	10037
TOP256EG	Power Integrations	TOPSwitch®-HX	Flyback	700V	66kHz, 132kHz	119	7-SSIP eSIP-7C	78%	-40 to 150	1266
TOP256EN	Power Integrations	TOPSwitch®-HX	Flyback	700V	66kHz, 132kHz	119	7-SSIP eSIP-7C	78%	-40 to 150	27159
TOP258EN	Power Integrations	TOPSwitch®-HX	Flyback	700V	66kHz, 132kHz	195	7-SSIP eSIP-7C	78%	-40 to 150	16620
TOP259EG	Power Integrations	TOPSwitch®-HX	Flyback	700V	66kHz, 132kHz	238	7-SSIP eSIP-7C	78%	-40 to 150	9200
TOP259EN	Power Integrations	TOPSwitch®-HX	Flyback	700V	66kHz, 132kHz	238	7-SSIP eSIP-7C	78%	-40 to 150	10100
TOP260EG	Power Integrations	TOPSwitch®-HX	Flyback	700V	66kHz, 132kHz	275	7-SSIP eSIP-7C	78%	-40 to 150	265600
TOP260EN	Power Integrations	TOPSwitch®-HX	Flyback	700V	66kHz, 132kHz	275	7-SSIP eSIP-7C	78%	-40 to 150	Data not provided

Engineering Selection Recommendations

Primary Selection Criteria:

Power Rating Alignment: Select a substitute part with power rating equal to or greater than the application requirement. The TOP257EN is rated at 157W. Suitable direct substitutes include TOP258EN (195W), TOP259EG/EN (238W), and TOP260EG/EN (275W). Lower-rated parts (TOP253EN through TOP256EN/EG) are not suitable for applications requiring 157W output.
Product Status and Compliance: All listed substitute parts maintain Active product status with full RoHS compliance and REACH unaffected designation. All parts carry ECCN EAR99 classification and HTSUS code 8542.39.0001, ensuring consistent regulatory standing.
Package and Mounting Compatibility: All substitute parts use identical 7-SSIP eSIP-7C package with through-hole mounting. PCB layout and thermal management designs require no modification for package-compatible substitutes.
Thermal Operating Range: All parts operate across -40°C to 150°C junction temperature range, maintaining consistent thermal specifications for system design.
Inventory Availability: TOP260EG demonstrates highest inventory (265,600 pcs), followed by TOP256EN (27,159 pcs) and TOP258EN (16,620 pcs). Consider inventory status for supply chain continuity.

Substitution Hierarchy for TOP257EN (157W):

First choice: TOP258EN (195W) - next power tier, 16,620 pcs available
Alternative: TOP259EN (238W) - higher margin, 10,100 pcs available
Alternative: TOP260EG (275W) - maximum rating, 265,600 pcs available

Frequently Asked Questions (FAQ)

Q1: Can I use a lower-power rated substitute like TOP256EN (119W) in place of TOP257EN (157W)?

A: No. The TOP256EN maximum power rating of 119W is insufficient for applications requiring 157W output. Using an undersized part will result in thermal stress, reduced efficiency, and potential component failure. Only equal or higher-rated parts are suitable.

Q2: Can I use a higher-power rated substitute like TOP260EG (275W) in place of TOP257EN (157W)?

A: Yes. Higher-rated parts operate within their design envelope at lower power levels. The TOP260EG can be used in 157W applications. Verify that PCB thermal management and layout accommodate the device without modification. No circuit redesign is required.

Q3: What is the difference between TOP259EG and TOP259EN?

A: Both parts are identical in electrical specifications and power rating (238W). The suffix designates packaging variant or manufacturing location. Both are functionally equivalent for TOP257EN substitution. Selection may depend on inventory availability or supplier preference.

Q4: Are all substitute parts pin-compatible with TOP257EN?

A: Yes. All listed substitutes use the 7-SSIP eSIP-7C package with 6 leads and exposed pad. Pin configuration and lead spacing are identical, enabling direct PCB replacement without layout modification.

Q5: Do substitute parts require different external component values?

A: External component selection (transformer, capacitors, resistors) depends on the specific power rating and application topology. While all parts share identical switching frequency (66kHz/132kHz), duty cycle (78%), and protection features, transformer design and output filtering may require adjustment based on the selected power rating. Consult Power Integrations design guidelines for the specific substitute part.

Q6: What is the significance of the "EN" and "EG" suffixes?

A: These designations indicate manufacturing or packaging variants within the TOPSwitch®-HX series. Both variants maintain identical electrical and thermal specifications. Selection between EN and EG variants is typically based on inventory availability or regional supplier preference, with no functional difference for substitution purposes.

Q7: Are all substitute parts RoHS compliant?

A: Yes. All listed substitute parts carry RoHS Compliant status with MSL 1 (Unlimited) moisture sensitivity rating. Regulatory compliance is maintained across the entire substitution range.

Q8: Can I substitute TOP257EN with multiple different part numbers in the same production run?

A: Yes, provided all selected substitutes meet the application power requirement and maintain identical package specifications. However, for consistency in thermal management and reliability testing, it is preferable to standardize on a single substitute part number within a production batch.

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