FSL136MRTWDTU Equivalent & Substitute Parts

Part Overview

The FSL136MRTWDTU is an offline flyback converter IC manufactured by onsemi, designed for isolated power management applications. This device operates at 67kHz switching frequency with 50W power capability and integrates internal switching functionality within a TO-220-6 package. The product is currently obsolete, making equivalent and substitute parts necessary for ongoing design support, legacy system maintenance, and production continuity.

Substiute Parts

FSL136MRTWDTU

onsemiIn Stock: 2119FSL136MRTWDTU Datasheet

Current PartRFQ

NCP11185A065PG

onsemiIn Stock: 3413NCP11185A065PG Datasheet

SimilarRFQ

FSL126MRTWDTU

onsemiIn Stock: 1190FSL126MRTWDTU Datasheet

Parametric EquivalentRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitution for the FSL136MRTWDTU is determined by the following critical parameters: isolated flyback topology, internal integrated switch, voltage breakdown rating of 650V or higher, supply voltage range compatibility (7.5V ~ 26V), switching frequency proximity (67kHz), power rating capability (50W minimum), fault protection features, and through-hole mounting compatibility.

The substitute parts are grouped into two categories:

Parametric Equivalent: FSL126MRTWDTU shares identical topology, package form factor, switching frequency, supply voltage range, and fault protection architecture. This part differs only in power rating (40W versus 50W) and represents the closest functional equivalent within the same product series.

Similar Functional Substitute: NCP11185A065PG provides flyback topology with isolated output and comparable fault protection. This part operates at 65kHz switching frequency with higher voltage breakdown (800V) and increased power capability (55W), but differs in package type (7-PDIP versus TO-220-6), internal switch configuration (no internal switch), and supply voltage range (7.8V ~ 16V).

Parameter Comparison

Engineering Selection Recommendations

FSL126MRTWDTU is the preferred parametric equivalent for direct replacement in applications where 40W power output is sufficient. Both parts share identical electrical characteristics, package form factor, and thermal operating range. Both products carry obsolete status; however, FSL126MRTWDTU maintains higher inventory availability (1122 pcs) compared to FSL136MRTWDTU (2045 pcs). This part requires no circuit redesign for pin-compatible substitution.

NCP11185A065PG is suitable for applications requiring active product status and extended temperature operation (-40°C ~ 150°C). This part provides higher power capability (55W) and superior voltage breakdown rating (800V). Selection of this substitute requires circuit redesign due to package change from TO-220-6 to 7-PDIP, absence of internal switch (requiring external switching components), and modified supply voltage range (7.8V ~ 16V maximum versus 26V). The lower startup voltage (2.1V) may provide advantages in low-input-voltage applications.

All substitute parts maintain ROHS3 compliance and REACH unaffected status, ensuring regulatory continuity.

Frequently Asked Questions (FAQ)

Q: Can FSL126MRTWDTU directly replace FSL136MRTWDTU in existing designs?

A: Yes, FSL126MRTWDTU provides pin-compatible substitution with identical package, pinout, and electrical interface. The primary difference is reduced power rating (40W versus 50W). Direct replacement is suitable for applications operating below 40W output power without circuit modification.

Q: What are the key differences between FSL136MRTWDTU and NCP11185A065PG?

A: The primary differences are package type (TO-220-6 versus 7-PDIP), internal switch presence (integrated versus external requirement), supply voltage range (7.5V-26V versus 7.8V-16V), and product status (obsolete versus active). NCP11185A065PG requires circuit redesign and external switching components but offers higher power capability and active manufacturing status.

Q: Is NCP11185A065PG a drop-in replacement for FSL136MRTWDTU?

A: No. NCP11185A065PG requires circuit redesign due to different package footprint, absence of internal switch, and modified electrical specifications. This part is suitable only for new designs or complete circuit rework.

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

A: NCP11185A065PG is recommended for new designs due to active product status and ongoing manufacturer support. FSL126MRTWDTU and FSL136MRTWDTU are both obsolete and should be used only for legacy system maintenance or existing inventory utilization.

Q: Are all substitute parts RoHS compliant?

A: Yes. FSL136MRTWDTU, FSL126MRTWDTU, and NCP11185A065PG are all ROHS3 compliant and REACH unaffected, meeting current environmental and regulatory requirements.

Q: What is the impact of different switching frequencies (67kHz versus 65kHz)?

A: The 2kHz frequency difference between FSL136MRTWDTU (67kHz) and NCP11185A065PG (65kHz) is negligible for most applications. Transformer and filter component designs may require minor adjustment, but functional compatibility remains within standard engineering tolerances.