IXTH21N50Q Equivalent & Substitute Parts

Part Overview

The IXTH21N50Q is an N-Channel MOSFET rated for 500V drain-to-source voltage with 21A continuous drain current and 300W power dissipation. Manufactured by IXYS in the HiPerFET™ series, this device is packaged in TO-247AD through-hole configuration. The part is currently obsolete, necessitating identification of functionally equivalent alternatives for ongoing system support and new designs.

Substiute Parts

IXTH21N50Q

IXYSIn Stock: 953IXTH21N50Q Datasheet

Current PartRFQ

FDP22N50N

onsemiIn Stock: 2177FDP22N50N Datasheet

DirectRFQ

IRFP460APBF

Vishay SiliconixIn Stock: 2810IRFP460APBF Datasheet

SimilarRFQ

IRFP460LCPBF

Vishay SiliconixIn Stock: 1761IRFP460LCPBF Datasheet

SimilarRFQ

STW20NM50FD

STMicroelectronicsIn Stock: 6567STW20NM50FD Datasheet

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Key Parameters

Substitute Part Grouping Explanation

Substitution of the IXTH21N50Q is determined by the following critical parameters:

Electrical Compatibility Requirements:

• Drain-to-source voltage rating must equal or exceed 500V
• Continuous drain current must meet or exceed 21A at 25°C
• On-state resistance characteristics must support equivalent power handling
• Gate threshold voltage and gate charge must be compatible with existing drive circuitry
• Operating temperature range must encompass -55°C to 150°C

Mechanical Compatibility Requirements:

• Through-hole mounting type required
• Package footprint must be compatible with TO-247 series configurations (TO-247AD, TO-247AC, or TO-247-3)

The substitute parts listed below satisfy these electrical and mechanical criteria within the allowed parameter tolerances for this MOSFET category.

Parameter Comparison

Engineering Selection Recommendations

FDP22N50N (onsemi UniFET™)

The FDP22N50N provides the highest current rating (22A) among available substitutes and exceeds the IXTH21N50Q in power dissipation (312.5W vs. 300W). This part is active and RoHS3 compliant. The primary consideration is package transition from TO-247AD to TO-220-3, which requires PCB layout modification. The lower gate charge (65 nC) offers improved switching performance compared to the original part.

IRFP460APBF and IRFP460LCPBF (Vishay Siliconix)

Both variants maintain the TO-247AC package footprint, minimizing mechanical redesign. Current rating is 20A, slightly below the original 21A specification. Power dissipation is 280W, lower than the IXTH21N50Q. Both parts are active and RoHS3 compliant. IRFP460APBF is REACH unaffected; IRFP460LCPBF is REACH affected. Gate charge differs between variants (105 nC vs. 120 nC), affecting switching characteristics.

STW20NM50FD (STMicroelectronics FDmesh™)

The STW20NM50FD maintains TO-247-3 package compatibility and is active with RoHS3 compliance. Current rating is 20A with 250 mOhm on-state resistance matching the original specification. Power dissipation is 214W, the lowest among substitutes. Gate charge is 53 nC, the lowest available, providing superior switching performance. Operating temperature specification lists only maximum (150°C) without lower bound documentation.

Frequently Asked Questions (FAQ)

Q: Can the FDP22N50N replace the IXTH21N50Q directly on the existing PCB?

A: The FDP22N50N uses TO-220-3 packaging versus the original TO-247AD. While both are through-hole configurations, the pin spacing and lead geometry differ, requiring PCB layout modification. Direct socket substitution is not possible.

Q: What is the significance of the gate charge (Qg) differences among substitutes?

A: Gate charge determines the energy required to switch the MOSFET on and off. The IXTH21N50Q requires 190 nC. Substitutes range from 53 nC (STW20NM50FD) to 190 nC (FDP22N50N). Lower gate charge reduces switching losses and allows faster switching speeds with the same drive circuit. Higher gate charge may require increased drive current or extended switching times.

Q: Are all substitute parts suitable for the same thermal environment?

A: All parts operate to 150°C maximum junction temperature. The IXTH21N50Q and most substitutes specify -55°C minimum operating temperature. The STW20NM50FD documentation provides only the maximum temperature specification. Thermal design must account for the lower power dissipation ratings of IRFP460 variants (280W) and STW20NM50FD (214W) compared to the original 300W specification.

Q: What compliance certifications apply to each substitute?

A: FDP22N50N is RoHS3 compliant and REACH unaffected. IRFP460APBF is RoHS3 compliant and REACH unaffected. IRFP460LCPBF is RoHS3 compliant and REACH affected. STW20NM50FD is RoHS3 compliant and REACH unaffected. All parts carry EAR99 export classification.

Q: How do on-state resistance values affect circuit performance?

A: On-state resistance (Rds On) directly determines conduction losses. The IXTH21N50Q specifies 250 mOhm at 10.5A and 10V gate drive. FDP22N50N offers 220 mOhm at 11A (improved), IRFP460 variants specify 270 mOhm at 12A (degraded), and STW20NM50FD specifies 250 mOhm at 10A (equivalent). Lower resistance reduces power dissipation and heat generation in high-current applications.

Q: Which substitute provides the closest electrical match to the original part?

A: STW20NM50FD and IRFP460LCPBF maintain identical Vdss (500V) and similar Rds On characteristics. STW20NM50FD offers superior gate charge performance (53 nC) and maintains TO-247-3 package compatibility. IRFP460LCPBF provides TO-247AC package compatibility with gate charge of 120 nC. Current rating is 20A for both, compared to 21A for the original.