STW15NK50Z N-Channel 500V 14A MOSFET Equivalent & Substitute Parts

Part Overview

The STW15NK50Z is an N-Channel MOSFET manufactured by STMicroelectronics, rated for 500V drain-to-source voltage with 14A continuous drain current at 25°C. This device is packaged in TO-247-3 through-hole configuration and is part of the SuperMESH™ series. The part is designated as "Not For New Designs," indicating it has been superseded in the product lifecycle. Identification of equivalent and substitute parts is necessary for applications requiring continued supply, design flexibility, or performance optimization within the 500V N-Channel MOSFET category.

Key Parameters

Parameter	Value	Unit
Drain-to-Source Voltage (Vdss)	500	V
Continuous Drain Current (Id) @ 25°C	14	A
On-State Resistance (Rds On) @ 7A, 10V	340	mOhm
Gate Threshold Voltage (Vgs(th)) @ 100µA	4.5	V
Gate Charge (Qg) @ 10V	106	nC
Power Dissipation (Max)	160	W
Operating Temperature Range	-50 to 150	°C
Package Type	TO-247-3	—
Mounting Type	Through Hole	—

Substitute Part Grouping Explanation

Substitution of the STW15NK50Z is determined by strict adherence to the following electrical and mechanical parameters:

Critical Matching Parameters:

Drain-to-Source Voltage (Vdss): 500V (exact match required)
FET Type: N-Channel (exact match required)
Technology: MOSFET Metal Oxide (exact match required)
Package/Case: TO-247-3 (exact match required)
Mounting Type: Through Hole (exact match required)

Performance Compatibility Parameters:

Continuous Drain Current (Id) @ 25°C: Equal to or greater than 14A
On-State Resistance (Rds On): Equal to or lower than 340mOhm (at comparable test conditions)
Gate Threshold Voltage (Vgs(th)): Within ±30V gate voltage specification
Power Dissipation: Equal to or greater than 160W
Operating Temperature Range: Must encompass -50°C to 150°C minimum

Substitute parts are grouped into three categories based on drain current rating: direct equivalents (14A), higher-current alternatives (16A–22A), and high-current alternatives (44A). All substitute parts maintain 500V Vdss rating and TO-247-3 package configuration.

Parameter Comparison

Manufacturer Part Number	Manufacturer	Vdss (V)	Id @ 25°C (A)	Rds On (mOhm)	Qg @ 10V (nC)	Power Dissipation (W)	Temp Range (°C)	Product Status
STW15NK50Z	STMicroelectronics	500	14	340 @ 7A	106	160	-50 to 150	Not For New Designs
IRFP450APBF	Vishay Siliconix	500	14	400 @ 8.4A	64	190	-55 to 150	Active
IRFP450LCPBF	Vishay Siliconix	500	14	400 @ 8.4A	74	190	-55 to 150	Active
IRFP450PBF	Infineon Technologies	500	14	400 @ 8.4A	150	190	-55 to 150	Obsolete
IRFP17N50LPBF	Vishay Siliconix	500	16	320 @ 9.9A	130	220	-55 to 150	Active
IRFP22N50APBF	Vishay Siliconix	500	22	230 @ 13A	120	277	-55 to 150	Active
IRFP460APBF	Vishay Siliconix	500	20	270 @ 12A	105	280	-55 to 150	Active
IRFP460LCPBF	Vishay Siliconix	500	20	270 @ 12A	120	280	-55 to 150	Active
IRFP460LC	Vishay Siliconix	500	20	270 @ 12A	120	280	-55 to 150	Active
APT20F50B	Microsemi Corporation	500	20	300 @ 10A	75	290	-55 to 150	Active
FDH44N50	onsemi	500	44	120 @ 22A	108	750	-55 to 175	Active

Engineering Selection Recommendations

Direct Current Rating Equivalents (14A):

IRFP450APBF and IRFP450LCPBF are functionally equivalent to STW15NK50Z at the 14A continuous drain current rating. Both devices are manufactured by Vishay Siliconix and carry Active product status. IRFP450APBF exhibits lower gate charge (64 nC) compared to the STW15NK50Z (106 nC), resulting in faster switching characteristics. IRFP450LCPBF provides intermediate gate charge (74 nC) and is recommended for applications requiring balanced switching performance. Both parts are ROHS3 compliant and rated for -55°C to 150°C operating temperature, extending the lower temperature limit by 5°C relative to the main part.

IRFP450PBF, manufactured by Infineon Technologies, is designated Obsolete and is not recommended for new applications despite electrical compatibility.

Higher Current Alternatives (16A–22A):

IRFP17N50LPBF (16A) and IRFP22N50APBF (22A) provide increased current handling capacity with improved on-state resistance characteristics. IRFP17N50LPBF delivers 320 mOhm on-state resistance at 9.9A, representing a 6% improvement over the STW15NK50Z. IRFP22N50APBF achieves 230 mOhm on-state resistance at 13A, providing 32% lower resistance and 73% higher power dissipation rating (277W). Both devices are Active status and ROHS3 compliant.

IRFP460APBF and IRFP460LCPBF (20A rating) occupy the intermediate current range with 270 mOhm on-state resistance and 280W power dissipation. IRFP460APBF is ROHS3 compliant; IRFP460LCPBF is RoHS non-compliant. IRFP460LC (20A) is functionally identical to IRFP460LCPBF with Active status.

APT20F50B, manufactured by Microsemi Corporation, provides 20A continuous drain current with 300 mOhm on-state resistance and 290W power dissipation. This device is ROHS3 compliant and Active status.

High Current Alternative (44A):

FDH44N50, manufactured by onsemi, provides 44A continuous drain current with significantly reduced on-state resistance (120 mOhm at 22A). This device is suitable for applications requiring substantially higher current capacity with improved thermal performance. FDH44N50 is rated for -55°C to 175°C operating temperature, extending the upper temperature limit by 25°C. The device is Active status and ROHS3 compliant.

Compliance and Regulatory Status:

All recommended substitute parts are ROHS3 compliant except IRFP460LC. All parts are REACH Unaffected or REACH Affected as specified. ECCN classification is EAR99 for all parts. Moisture Sensitivity Level is 1 (Unlimited) for all parts except FDH44N50 (Not Applicable).

Frequently Asked Questions (FAQ)

Q: Can IRFP450APBF directly replace STW15NK50Z in existing designs?

A: IRFP450APBF is electrically compatible as a direct replacement. Both devices share identical 500V Vdss rating, 14A continuous drain current, and TO-247-3 package configuration. IRFP450APBF exhibits lower gate charge (64 nC versus 106 nC), resulting in faster switching response. Thermal performance is superior (190W versus 160W power dissipation). Operating temperature range extends to -55°C (versus -50°C minimum). No circuit modifications are required for substitution.

Q: What is the difference between IRFP460APBF and IRFP460LCPBF?

A: Both devices are rated for 500V Vdss and 20A continuous drain current with identical on-state resistance (270 mOhm at 12A). The primary difference is gate charge specification: IRFP460APBF is specified at 105 nC while IRFP460LCPBF is specified at 120 nC. IRFP460APBF is ROHS3 compliant; IRFP460LCPBF is RoHS non-compliant. Both are Active status and suitable for 500V applications requiring 20A current capacity.

Q: When should FDH44N50 be selected over lower-current alternatives?

A: FDH44N50 is selected when application requirements exceed 22A continuous drain current or when reduced on-state resistance is critical for thermal management. The 120 mOhm on-state resistance (at 22A) is substantially lower than alternatives, reducing conduction losses. The 750W power dissipation rating accommodates high-power applications. Extended operating temperature range (-55°C to 175°C) supports demanding thermal environments. FDH44N50 is not a direct replacement for STW15NK50Z but rather a performance-enhanced alternative for higher-power designs.

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

A: All substitute parts listed are packaged in TO-247-3 or TO-247AC configuration, which are mechanically and electrically compatible through-hole packages. Pin assignments and mounting footprints are identical across all listed parts. No PCB modifications are required for package compatibility.

Q: What is the significance of "Not For New Designs" status on STW15NK50Z?

A: "Not For New Designs" indicates that STMicroelectronics has discontinued active development and marketing of this part. Existing inventory may remain available, but the manufacturer recommends using alternative parts for new applications. Active-status alternatives such as IRFP450APBF, IRFP460APBF, or IRFP22N50APBF are recommended for new designs to ensure long-term supply continuity and access to manufacturer technical support.

Q: How do gate charge specifications affect circuit performance?

A: Gate charge (Qg) determines the energy required to switch the MOSFET on and off. Lower gate charge enables faster switching transitions and reduces driver power consumption. STW15NK50Z specifies 106 nC gate charge, while IRFP450APBF specifies 64 nC. In high-frequency switching applications, IRFP450APBF reduces switching losses and improves efficiency. In low-frequency applications, gate charge differences have minimal impact on overall performance.

Q: Is thermal management affected by on-state resistance differences?

A: On-state resistance (Rds On) directly determines conduction losses according to the relationship P = I²R. Lower Rds On reduces heat generation at equivalent current levels. IRFP22N50APBF (230 mOhm at 13A) generates approximately 32% less heat than STW15NK50Z (340 mOhm at 7A) at comparable operating points. Applications with stringent thermal constraints benefit from lower Rds On alternatives. Conversely, applications with adequate thermal design margin may not require Rds On optimization.

Q: What compliance certifications are critical for component selection?

A: ROHS3 compliance is mandatory for applications subject to European Union Restriction of Hazardous Substances regulations. All recommended substitute parts except IRFP460LC are ROHS3 compliant. REACH compliance status varies; REACH Unaffected parts are preferred for applications in regulated markets. ECCN classification (EAR99) indicates standard commercial electronics with no export restrictions. Moisture Sensitivity Level 1 (Unlimited) indicates no special moisture handling requirements during storage or assembly.

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