IXFM42N20 Equivalent & Substitute Parts

Part Overview

The IXFM42N20 is an N-Channel MOSFET rated for 200V drain-to-source voltage with a continuous drain current of 42A at 25°C. This device is manufactured by IXYS under the HiPerFET™ series and is housed in a TO-204AE through-hole package. The part is classified as obsolete, making identification of functionally equivalent alternatives necessary for ongoing design support, maintenance, and production continuity. Substitute parts must maintain electrical compatibility across voltage, current, and thermal specifications while accommodating potential package differences in board-level integration.

Substiute Parts

IXFM42N20

IXYSIn Stock: 2360IXFM42N20 Datasheet

Current PartRFQ

IRFB38N20DPBF

International RectifierIn Stock: 30114IRFB38N20DPBF Datasheet

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Key Parameters

Substitute Part Grouping Explanation

Substitution of the IXFM42N20 is based on electrical parameter equivalence within defined tolerances. The primary substitution criteria are:

Electrical Compatibility Requirements:

• Drain-to-Source Voltage (Vdss): Must equal or exceed 200V
• Continuous Drain Current (Id): Must equal or exceed 42A at 25°C
• On-State Resistance (Rds On): Must not significantly exceed the original specification to maintain thermal performance
• Gate Charge (Qg): Lower values indicate improved switching efficiency
• Power Dissipation: Must support 300W thermal rating at Tc

Mechanical Compatibility Considerations:

• Mounting type must remain through-hole
• Package form factor may differ (TO-204AE vs. TO-220AB) but must be compatible with existing PCB layouts or require documented rework procedures

The IRFB38N20DPBF meets these criteria with equivalent voltage and current ratings, comparable on-state resistance, and active product status, making it a direct functional substitute despite package differences.

Parameter Comparison

Engineering Selection Recommendations

IRFB38N20DPBF as Primary Substitute:

The IRFB38N20DPBF is classified as an active product, providing long-term availability and manufacturing support compared to the obsolete IXFM42N20. Electrical parameters are equivalent or superior: the substitute delivers 43A continuous drain current (versus 42A), maintains 200V Vdss rating, and provides lower on-state resistance (54 mOhm versus 60 mOhm), resulting in reduced power dissipation and improved thermal efficiency.

The substitute exhibits lower gate charge (91 nC versus 220 nC), enabling faster switching transitions and reduced driver power requirements. Input capacitance is also reduced (2900 pF versus 4400 pF), further improving switching performance.

Package Consideration:

The primary difference is package form factor: IXFM42N20 uses TO-204AE while IRFB38N20DPBF uses TO-220-3. Both are through-hole packages with different pin configurations and thermal characteristics. PCB layout modifications or adapter solutions may be required for direct replacement. The TO-220-3 package provides improved thermal dissipation through enhanced lead structure, supporting the 300W power rating.

Compliance Status:

The IXFM42N20 is ROHS3 compliant. The IRFB38N20DPBF compliance status is not specified in available documentation. Verification of RoHS and REACH compliance with the substitute manufacturer is required for applications subject to regulatory restrictions.

Frequently Asked Questions (FAQ)

Q: Can the IRFB38N20DPBF directly replace the IXFM42N20 without circuit modifications?

A: Electrical parameters are compatible for direct functional substitution. However, the package change from TO-204AE to TO-220-3 requires PCB layout evaluation. Pin assignments differ between packages, necessitating either PCB rework or use of an adapter solution. Thermal management characteristics also differ due to package geometry.

Q: What is the significance of the lower gate charge in the IRFB38N20DPBF?

A: Gate charge (Qg) of 91 nC versus 220 nC indicates reduced charge transfer requirements during switching transitions. This results in lower gate driver power consumption, faster switching speed, and reduced electromagnetic interference. Driver circuits designed for the original part will operate more efficiently with the substitute.

Q: Are there differences in thermal performance between these devices?

A: Both devices support 300W power dissipation at Tc (case temperature). The IRFB38N20DPBF operates to 175°C junction temperature versus 150°C for the IXFM42N20, providing extended thermal margin. The TO-220-3 package typically offers superior thermal coupling to heatsinks compared to TO-204AE, improving practical heat dissipation in board-level applications.

Q: What is the impact of the on-state resistance difference?

A: The IRFB38N20DPBF exhibits 54 mOhm on-state resistance versus 60 mOhm for the IXFM42N20. This 10% reduction decreases conduction losses and heat generation during operation, improving overall circuit efficiency and reducing thermal stress on the device and surrounding components.

Q: Is the IRFB38N20DPBF suitable for high-frequency switching applications?

A: The lower gate charge and input capacitance of the IRFB38N20DPBF support higher switching frequencies compared to the IXFM42N20. Applications requiring switching frequencies above the original design specification will benefit from the improved switching characteristics of the substitute.

Q: What documentation should be reviewed before implementing this substitution?

A: Obtain complete datasheets for both devices, focusing on pin configuration, thermal characteristics, and gate drive requirements. Verify PCB layout compatibility or plan rework procedures. Confirm RoHS and REACH compliance status with the substitute manufacturer if regulatory compliance is required. Evaluate thermal management strategy for the TO-220-3 package in the target application.