STW45NM50FD N-Channel 500V 45A MOSFET Equivalent & Substitute Parts

Part Overview

The STW45NM50FD is an N-Channel 500V 45A MOSFET manufactured by STMicroelectronics in the FDmesh™ series, housed in a TO-247-3 through-hole package. This device is rated for 417W maximum power dissipation and operates across a temperature range of -65°C to 150°C. The part is currently listed as obsolete, making identification of equivalent and substitute components essential for design continuity and procurement planning.

Substitute parts are necessary due to the obsolete status of the STW45NM50FD. Active alternatives with comparable electrical and mechanical specifications enable designers to maintain circuit functionality while sourcing from current product lines.

Substiute Parts

STW45NM50FD

STMicroelectronicsIn Stock: 1743STW45NM50FD Datasheet

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FDH45N50F-F133

onsemiIn Stock: 1052FDH45N50F-F133 Datasheet

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IXFH44N50P

IXYSIn Stock: 8434IXFH44N50P Datasheet

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IXTX60N50L2

IXYSIn Stock: 1225IXTX60N50L2 Datasheet

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SPW32N50C3FKSA1

Infineon TechnologiesIn Stock: 91316SPW32N50C3FKSA1 Datasheet

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Key Parameters

Substitute Part Grouping Explanation

Substitution eligibility for the STW45NM50FD is determined by the following critical parameters:

Primary Matching Criteria:

• FET Type: N-Channel
• Drain to Source Voltage (Vdss): 500V minimum
• Continuous Drain Current (Id): 45A or greater at 25°C
• Package/Mounting: Through-hole configuration compatible with TO-247-3 footprint
• Drive Voltage: 10V gate drive capability

Secondary Compatibility Factors:

• On-State Resistance (Rds On): Comparable performance at specified current and gate voltage
• Gate Threshold Voltage (Vgs(th)): Within acceptable range for circuit gate drive requirements
• Operating Temperature Range: Minimum -55°C to 150°C
• Regulatory Compliance: ROHS3 compliance and REACH unaffected status

The four substitute parts listed below meet these criteria with varying degrees of parameter alignment. Differences in gate charge, input capacitance, and power dissipation reflect design variations across manufacturers but do not preclude functional substitution when circuit requirements are satisfied.

Parameter Comparison

Engineering Selection Recommendations

FDH45N50F-F133 (onsemi UniFET™)

The FDH45N50F-F133 provides the closest electrical match to the STW45NM50FD with identical Vdss (500V) and Id (45A) ratings. This part is active in production and ROHS3 compliant. The slightly elevated Rds On (120mOhm vs. 100mOhm) and gate charge (137nC vs. 120nC) represent minor performance variations. The higher input capacitance (6630pF vs. 3600pF) may require gate drive circuit evaluation in high-frequency switching applications. Operating temperature range is -55°C to 150°C, which covers the upper portion of the original part's range. This substitute is suitable for direct replacement in most applications where the lower temperature limit of -55°C is acceptable.

IXFH44N50P (IXYS HiPerFET™)

The IXFH44N50P delivers 44A continuous drain current at 500V, representing a 2% reduction from the 45A specification. This part is active and ROHS3 compliant. The Rds On of 140mOhm is higher than the original, resulting in increased conduction losses. Gate charge is lower at 98nC, which may reduce switching losses in certain topologies. The TO-247AD package variant maintains through-hole compatibility with standard TO-247-3 footprints. This substitute is applicable where the slightly reduced current rating and higher on-state resistance are acceptable within circuit design margins.

IXTX60N50L2 (IXYS Linear L2™)

The IXTX60N50L2 exceeds the original specifications with 60A continuous drain current at 500V and superior Rds On performance (100mOhm at 30A). This part is active and ROHS3 compliant. The PLUS247™-3 package is a through-hole variant compatible with TO-247-3 footprints. Significantly elevated gate charge (610nC) and input capacitance (24000pF) indicate higher capacitive loading on gate drive circuits, requiring circuit analysis for switching frequency compatibility. This substitute is suitable for applications requiring enhanced current handling and thermal performance, provided gate drive capability is confirmed.

SPW32N50C3FKSA1 (Infineon CoolMOS™)

The SPW32N50C3FKSA1 operates at 560V Vdss with 32A continuous drain current, representing a 29% reduction in current rating compared to the original 45A specification. This part is active and ROHS3 compliant. The lower current rating restricts this substitute to applications with reduced current demands. The Rds On of 110mOhm and lower gate charge (170nC) provide acceptable switching characteristics. The maximum gate voltage is ±20V, compared to ±30V for the original part. This substitute is applicable only in circuits where the 32A current limit is sufficient and gate drive voltage does not exceed ±20V.

Frequently Asked Questions (FAQ)

Q: Can the FDH45N50F-F133 be used as a direct replacement for the STW45NM50FD?

A: The FDH45N50F-F133 is electrically compatible for most applications. Both parts share identical Vdss (500V) and Id (45A) ratings, TO-247-3 package compatibility, and ROHS3 compliance. The primary difference is the operating temperature minimum of -55°C versus -65°C for the original part. If your application operates above -55°C, this substitute is suitable. The slightly higher Rds On and gate charge require verification that circuit thermal and switching performance remain within design specifications.

Q: What is the key limitation of the SPW32N50C3FKSA1 as a substitute?

A: The SPW32N50C3FKSA1 has a continuous drain current rating of 32A, which is 29% lower than the STW45NM50FD's 45A rating. This part is only suitable for applications where the circuit current demand does not exceed 32A. Additionally, the maximum gate voltage is ±20V compared to ±30V for the original part, which may restrict use in certain gate drive topologies.

Q: Why does the IXTX60N50L2 have such high gate charge and input capacitance?

A: The IXTX60N50L2 is rated for 60A continuous drain current, exceeding the original 45A specification. The higher current capability results in larger die geometry and increased parasitic capacitances. Gate charge of 610nC and input capacitance of 24000pF reflect this larger device structure. These parameters directly impact gate drive circuit design and switching frequency performance. Circuit simulation or testing is necessary to confirm compatibility with existing gate drive circuits.

Q: Are all substitute parts available in the same package as the STW45NM50FD?

A: All substitute parts use through-hole packages compatible with TO-247-3 footprints. The FDH45N50F-F133 uses standard TO-247-3. The IXFH44N50P uses TO-247AD (IXFH variant). The IXTX60N50L2 uses PLUS247™-3. The SPW32N50C3FKSA1 uses PG-TO247-3-1. While these packages have different designations, they share the same three-lead through-hole pin configuration and are mechanically compatible with standard TO-247-3 PCB layouts.

Q: Which substitute part has the lowest on-state resistance?

A: The STW45NM50FD and IXTX60N50L2 both specify 100mOhm Rds On, representing the lowest values in the comparison. The STW45NM50FD is measured at 22.5A and 10V gate voltage, while the IXTX60N50L2 is measured at 30A and 10V gate voltage. The IXTX60N50L2's measurement at higher current provides additional confidence in low-loss performance at elevated current levels.

Q: What compliance certifications are common across all parts?

A: All parts listed—the main STW45NM50FD and all four substitutes—are ROHS3 compliant and REACH unaffected. This ensures regulatory compliance for applications subject to these standards. All parts carry ECCN classification EAR99 and HTSUS code 8541.29.0095, indicating consistent export and tariff classification.

Q: How do I determine which substitute is best for my application?

A: Selection depends on three primary factors: (1) current requirement—if your circuit requires 45A, use FDH45N50F-F133 or IXTX60N50L2; if 44A is acceptable, use IXFH44N50P; if 32A is sufficient, use SPW32N50C3FKSA1. (2) Operating temperature—if below -55°C is required, none of the active substitutes are suitable. (3) Gate drive circuit—if your gate drive is optimized for low capacitance, avoid IXTX60N50L2; if gate voltage is limited to ±20V, avoid all parts except SPW32N50C3FKSA1. Verify thermal performance by comparing power dissipation ratings against your circuit's expected losses.