KA5M0265RTU Equivalent & Substitute Parts

Part Overview

The KA5M0265RTU is an offline switching power supply controller manufactured by onsemi, designed for flyback and forward topology converters operating at 67kHz. This device integrates an internal power switch with comprehensive fault protection including current limiting, overload, overvoltage, and overtemperature protection. The part is classified as obsolete, making identification of suitable substitute components essential for ongoing system support and new design implementations.

Substiute Parts

KA5M0265RTU

onsemiIn Stock: 2425KA5M0265RTU Datasheet

Current PartRFQ

FSL126MRTWDTU

onsemiIn Stock: 1190FSL126MRTWDTU Datasheet

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Key Parameters

Substitute Part Grouping Explanation

Substitution of the KA5M0265RTU is determined by the following critical parameters:

• Topology Compatibility: The substitute must support flyback topology as the primary operating mode
• Voltage Ratings: Breakdown voltage of 650V and supply voltage range of 7.5V ~ 26V minimum
• Switching Frequency: 67kHz operation to maintain system timing and EMI characteristics
• Internal Switch Integration: Presence of integrated power switch
• Fault Protection: Current limiting, overload, overvoltage, and overtemperature protection capabilities
• Package Form Factor: TO-220 package family with through-hole mounting
• Electrical Specifications: Duty cycle and startup voltage parameters within acceptable operating margins

The FSL126MRTWDTU meets these substitution criteria while introducing enhanced specifications including isolated output, extended operating temperature range, and increased power handling capability.

Parameter Comparison

Engineering Selection Recommendations

Both the KA5M0265RTU and FSL126MRTWDTU are classified as obsolete products within the onsemi FPS™ series. Selection between these components should be based on the following engineering considerations:

KA5M0265RTU remains suitable for applications where the original design specifications are strictly maintained, including the 77% duty cycle and 15V startup voltage. The narrower operating temperature range (-25°C ~ 85°C) is appropriate for standard industrial environments.

FSL126MRTWDTU provides enhanced capabilities including isolated output, lower startup voltage (12V), and extended operating temperature range (-40°C ~ 125°C), making it suitable for applications requiring broader thermal performance or isolation requirements. The TO-220-6 package provides additional pin configuration flexibility compared to the TO-220-4 form factor.

Both components maintain identical REACH compliance status (REACH Unaffected) and ECCN classification (EAR99), ensuring equivalent regulatory standing for procurement and export purposes.

Frequently Asked Questions (FAQ)

Q: Can FSL126MRTWDTU directly replace KA5M0265RTU in existing designs?

A: Direct replacement requires verification of three factors: (1) PCB layout compatibility with TO-220-6 versus TO-220-4 package geometry, (2) circuit tolerance for the lower startup voltage (12V vs 15V), and (3) acceptance of the lower duty cycle specification (67% vs 77%). Pin configuration differences between the 4-lead and 6-lead packages necessitate schematic review.

Q: What is the significance of the output isolation specification?

A: The FSL126MRTWDTU includes isolated output, while the KA5M0265RTU does not specify this parameter. Isolation affects ground reference architecture and may require circuit modifications in applications where isolation is a system requirement.

Q: Are both parts suitable for new designs?

A: Both components carry obsolete product status. For new designs, consultation with onsemi regarding current-generation FPS™ series alternatives is recommended to ensure long-term supply availability and access to manufacturing support.

Q: What are the package compatibility considerations?

A: The KA5M0265RTU uses TO-220-4 Full Pack, while FSL126MRTWDTU uses TO-220-6 Full Pack with formed leads. The 6-lead configuration provides additional connection points. PCB footprint redesign is necessary for substitution, and formed lead geometry may affect insertion and soldering processes.

Q: How do the operating temperature ranges affect application suitability?

A: The KA5M0265RTU operates from -25°C to 85°C (ambient), while FSL126MRTWDTU operates from -40°C to 125°C (junction). The FSL126MRTWDTU supports extended temperature applications including cold-start environments and high-ambient-temperature installations without thermal derating.