STW29NK50Z N-Channel 500V 31A MOSFET Equivalent & Substitute Parts

Part Overview

The STW29NK50Z is an N-Channel MOSFET manufactured by STMicroelectronics in the SuperMESH™ series, rated for 500V drain-to-source voltage with 31A continuous drain current at 25°C. This device is packaged in TO-247-3 through-hole configuration and is rated for 350W maximum power dissipation. The part is currently listed as obsolete, making equivalent and substitute parts necessary for ongoing design support and procurement.

Key Parameters

Parameter	Value	Unit
Drain to Source Voltage (Vdss)	500	V
Continuous Drain Current (Id) @ 25°C	31	A
On-State Resistance (Rds On Max) @ 10V	130	mOhm
Gate Threshold Voltage (Vgs th) Max	4.5	V @ 150µA
Gate Charge (Qg) Max @ 10V	266	nC
Input Capacitance (Ciss) Max @ 25V	6110	pF
Power Dissipation Max (Tc)	350	W
Operating Temperature Range	-55 to 150	°C
Package Type	TO-247-3	Through Hole
Gate Voltage Max	±30	V

Substitute Part Grouping Explanation

Substitution of the STW29NK50Z is determined by strict adherence to the following electrical and mechanical parameters:

Critical Matching Parameters:

Drain to Source Voltage (Vdss): 500V minimum
Package Type: TO-247-3 through-hole configuration
Gate Voltage Rating (Vgs Max): ±30V
Operating Temperature Range: -55°C to 150°C minimum
RoHS3 Compliance and REACH Unaffected status

Performance Parameters for Substitution Compatibility:

Continuous Drain Current (Id): Equal to or greater than 31A
On-State Resistance (Rds On): Equal to or less than 130mOhm at 10V drive voltage
Gate Threshold Voltage (Vgs th): Within ±30V gate voltage specification
Power Dissipation: Equal to or greater than 350W

Substitute parts must meet or exceed all critical matching parameters while maintaining electrical performance within the specified ranges. Parts with higher current ratings, lower on-state resistance, or greater power dissipation capability are acceptable as direct substitutes provided all other parameters remain compatible.

Parameter Comparison

Parameter	STW29NK50Z (Main)	IRFP31N50LPBF	FDH44N50	APT42F50B	APT5014BLLG
Manufacturer	STMicroelectronics	Vishay Siliconix	onsemi	Microchip Technology	Microchip Technology
Product Status	Obsolete	Active	Active	Active	Active
Vdss (V)	500	500	500	500	500
Id @ 25°C (A)	31	31	44	42	35
Rds On Max @ 10V (mOhm)	130	180	120	130	140
Vgs th Max @ Id (V)	4.5 @ 150µA	5 @ 250µA	4 @ 250µA	5 @ 1mA	5 @ 1mA
Qg Max @ 10V (nC)	266	210	108	170	72
Ciss Max @ 25V (pF)	6110	5000	5335	6810	3261
Power Dissipation Max (W)	350	460	750	625	403
Operating Temperature (°C)	-55 to 150	-55 to 150	-55 to 175	-55 to 150	-55 to 150
Package	TO-247-3	TO-247AC	TO-247-3	TO-247 [B]	TO-247 [B]
Vgs Max (V)	±30	±30	±30	±30	±30
RoHS3 Compliant	Yes	Yes	Yes	Yes	Yes
REACH Unaffected	Yes	Yes	Yes	Yes	Yes

Engineering Selection Recommendations

IRFP31N50LPBF (Vishay Siliconix)

This part provides direct electrical equivalence to the STW29NK50Z with identical 500V/31A ratings. The IRFP31N50LPBF is actively manufactured and maintains full RoHS3 compliance and REACH unaffected status. The TO-247AC package is mechanically compatible with TO-247-3 applications. Higher power dissipation rating (460W vs. 350W) provides thermal margin. This substitute is suitable for direct replacement in existing designs.

FDH44N50 (onsemi)

The FDH44N50 exceeds the STW29NK50Z specifications with 44A continuous drain current and 750W power dissipation. On-state resistance is superior at 120mOhm. The part maintains 500V Vdss rating and TO-247-3 package compatibility. Operating temperature range extends to 175°C. Active product status with full compliance certifications. This substitute provides enhanced performance headroom for thermal and current-handling requirements.

APT42F50B (Microchip Technology)

The APT42F50B offers 42A continuous drain current with 625W power dissipation, exceeding the STW29NK50Z baseline. Rds On specification matches at 130mOhm. 500V Vdss and ±30V gate voltage ratings are maintained. TO-247 [B] package is mechanically compatible with TO-247-3 through-hole applications. Active product status with full RoHS3 and REACH compliance. Suitable for applications requiring higher current capacity.

APT5014BLLG (Microchip Technology)

The APT5014BLLG provides 35A continuous drain current with 403W power dissipation, closely matching the STW29NK50Z current rating. Gate charge is significantly reduced at 72nC versus 266nC, resulting in faster switching characteristics. Input capacitance is substantially lower at 3261pF. 500V Vdss and TO-247 [B] package compatibility are maintained. Active product status with full compliance. This substitute is optimal for applications prioritizing switching speed and gate drive efficiency.

Frequently Asked Questions (FAQ)

Q: Can the IRFP31N50LPBF directly replace the STW29NK50Z in existing PCB layouts?

A: The IRFP31N50LPBF is mechanically and electrically compatible. Both devices use TO-247-3 package variants (TO-247AC and TO-247-3) with identical pin configurations and through-hole mounting. PCB layouts require no modification. Electrical performance is equivalent at the 31A/500V rating.

Q: What is the primary difference between the FDH44N50 and APT42F50B substitutes?

A: Both parts exceed the STW29NK50Z specifications. The FDH44N50 provides superior on-state resistance (120mOhm vs. 130mOhm) and higher power dissipation (750W vs. 625W). The APT42F50B offers slightly lower current rating (42A vs. 44A) but maintains the 130mOhm Rds On specification. Selection depends on thermal and current requirements of the specific application.

Q: Why does the APT5014BLLG have significantly lower gate charge than other substitutes?

A: The APT5014BLLG is from the POWER MOS 7® series, which incorporates different semiconductor technology compared to the SuperMESH™ series of the STW29NK50Z. Lower gate charge (72nC vs. 266nC) results in reduced gate drive power requirements and faster switching transitions. This is a design characteristic of the device technology, not a deficiency.

Q: Are all substitute parts RoHS3 compliant and REACH unaffected?

A: Yes. All four substitute parts (IRFP31N50LPBF, FDH44N50, APT42F50B, and APT5014BLLG) are RoHS3 compliant and REACH unaffected, matching the compliance status of the STW29NK50Z.

Q: Can I use the FDH44N50 in a design originally specified for the STW29NK50Z without circuit modifications?

A: Yes. The FDH44N50 meets or exceeds all critical electrical parameters of the STW29NK50Z. Higher current rating (44A vs. 31A) and power dissipation (750W vs. 350W) provide additional performance margin. No circuit modifications are required. Gate drive characteristics are compatible within the ±30V specification.

Q: What is the difference between TO-247-3 and TO-247 [B] packages?

A: Both package designations refer to the same three-lead through-hole configuration with identical pin spacing and mounting footprint. TO-247-3 and TO-247 [B] are mechanically interchangeable. Differences are manufacturer-specific nomenclature conventions.

Q: Which substitute part has the lowest switching losses?

A: The APT5014BLLG exhibits the lowest gate charge (72nC) and lowest input capacitance (3261pF), resulting in reduced switching losses compared to other substitutes. This characteristic makes it optimal for high-frequency switching applications where gate drive efficiency is critical.

Q: Is the STW29NK50Z still available for procurement?

A: The STW29NK50Z is listed as obsolete. Active substitute parts with equivalent or superior specifications are available from multiple manufacturers: IRFP31N50LPBF (Vishay Siliconix), FDH44N50 (onsemi), APT42F50B (Microchip Technology), and APT5014BLLG (Microchip Technology).

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