STF35N65M5 Equivalent & Substitute Parts

Part Overview

The STF35N65M5 is an N-Channel 650V 27A MOSFET manufactured by STMicroelectronics, part of the MDmesh™ V series. This device is designed for through-hole applications in the TO-220FP package and is rated for 40W power dissipation at case temperature. The part is currently classified as obsolete, making identification of equivalent and substitute components necessary for ongoing design support, maintenance, and production continuity.

Substiute Parts

STF35N65M5

STMicroelectronicsIn Stock: 1132STF35N65M5 Datasheet

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STF38N65M5

STMicroelectronicsIn Stock: 2308STF38N65M5 Datasheet

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AOTF42S60L

Alpha & Omega Semiconductor Inc.In Stock: 1233AOTF42S60L Datasheet

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Key Parameters

Substitute Part Grouping Explanation

Substitution of the STF35N65M5 is determined by the following critical electrical and mechanical parameters:

Voltage Rating (Vdss): The drain-to-source voltage must be equal to or greater than 650V to maintain system safety margins and prevent breakdown under peak operating conditions.

Current Rating (Id): The continuous drain current must be equal to or greater than 27A to support the load requirements without thermal stress.

On-State Resistance (Rds On): The maximum on-state resistance must be comparable or lower to ensure efficient power transfer and minimize heat generation.

Gate Charge (Qg): Lower gate charge values reduce switching losses and improve circuit efficiency.

Package Compatibility: The TO-220FP through-hole package is the mechanical requirement for direct board-level substitution.

Compliance Status: RoHS3 compliance and REACH unaffected status are mandatory for regulatory adherence.

Based on these criteria, two substitute parts are identified:

1. STF38N65M5 (STMicroelectronics): Same voltage class (650V), higher current rating (30A), lower Rds On (95mOhm), active product status, same package type.

2. AOTF42S60L (Alpha & Omega Semiconductor Inc.): Slightly lower voltage rating (600V), significantly higher current rating (39A), comparable Rds On (99mOhm), not for new designs status, same package family.

Parameter Comparison

Engineering Selection Recommendations

STF38N65M5 (Primary Substitute): This part is the preferred substitute for the STF35N65M5. It maintains the same 650V voltage rating and TO-220FP package configuration, ensuring direct compatibility with existing board layouts and circuit designs. The STF38N65M5 offers improved electrical performance with a higher continuous drain current (30A vs. 27A), lower on-state resistance (95mOhm vs. 98mOhm), and reduced gate charge (71nC vs. 83nC). The active product status ensures long-term availability and supply chain stability. RoHS3 compliance is maintained.

AOTF42S60L (Secondary Substitute): This part is suitable for applications where the 50V reduction in voltage rating (600V vs. 650V) is acceptable within system design margins. The AOTF42S60L provides significantly higher current capacity (39A vs. 27A) and substantially lower gate charge (40nC vs. 83nC), resulting in reduced switching losses. However, the "Not For New Designs" status indicates this part is in end-of-life phase and should be considered only for legacy system maintenance or where specific performance characteristics are required. The TO-220F package is mechanically compatible with TO-220FP footprints. RoHS3 compliance is maintained.

Both substitute parts meet regulatory compliance requirements and are available in production quantities.

Frequently Asked Questions (FAQ)

Q: Can the STF38N65M5 be used as a direct replacement for the STF35N65M5?

A: Yes. The STF38N65M5 is a direct substitute. Both parts share the same 650V voltage rating, TO-220FP package, and MDmesh™ V series technology. The STF38N65M5 provides equal or superior electrical performance across all critical parameters. No circuit modifications are required.

Q: What is the voltage rating difference between the STF35N65M5 and AOTF42S60L?

A: The STF35N65M5 is rated for 650V, while the AOTF42S60L is rated for 600V. This 50V difference must be evaluated against the maximum voltage stress in the application. If the system design includes margin above 600V, the AOTF42S60L is acceptable. If peak voltages approach or exceed 600V, the STF38N65M5 is the appropriate choice.

Q: Are the TO-220FP and TO-220F packages mechanically interchangeable?

A: The TO-220FP and TO-220F packages are mechanically compatible for through-hole board mounting. Both use three leads and fit standard TO-220 footprints. The "FP" designation indicates a full-pack variant, while "F" indicates a standard variant. Pin configuration and spacing are identical.

Q: Why is the STF35N65M5 classified as obsolete?

A: The STF35N65M5 has reached end-of-life status. The STF38N65M5 supersedes this part with improved performance characteristics and active manufacturing status. For new designs and ongoing production, the STF38N65M5 is the recommended choice.

Q: What is the significance of the "Not For New Designs" status of the AOTF42S60L?

A: This status indicates the AOTF42S60L is in end-of-life phase and is not recommended for new product development. It remains available for legacy system support and maintenance. For new designs, the STF38N65M5 is the preferred substitute.

Q: How does gate charge affect circuit performance?

A: Gate charge (Qg) determines the energy required to switch the MOSFET on and off. Lower gate charge reduces switching losses and improves efficiency. The STF38N65M5 (71nC) and AOTF42S60L (40nC) both offer lower gate charge than the STF35N65M5 (83nC), resulting in improved switching performance.

Q: Are all three parts RoHS3 compliant?

A: Yes. The STF35N65M5, STF38N65M5, and AOTF42S60L are all RoHS3 compliant and REACH unaffected, meeting current regulatory requirements for electronic components.