FDP24N40 Equivalent & Substitute Parts

Part Overview

The FDP24N40 is an N-Channel MOSFET manufactured by onsemi, rated for 400V drain-to-source voltage with 24A continuous drain current in a Through Hole TO-220-3 package. This device is classified as Obsolete, indicating it is no longer in active production. Identifying equivalent and substitute parts is necessary to maintain design continuity, ensure supply chain availability, and support ongoing applications where the FDP24N40 is currently deployed.

Key Parameters

Parameter	FDP24N40 Value
Drain to Source Voltage (Vdss)	400 V
Current - Continuous Drain (Id) @ 25°C	24 A (Tc)
Rds On (Max) @ Id, Vgs	175 mOhm @ 12A, 10V
Gate Charge (Qg) (Max) @ Vgs	60 nC @ 10 V
Power Dissipation (Max)	227 W (Tc)
Operating Temperature Range	-55°C ~ 150°C (TJ)
Package / Case	TO-220-3
Mounting Type	Through Hole

Substitute Part Grouping Explanation

Substitution of the FDP24N40 is determined by alignment across the following critical parameters:

Voltage Rating (Vdss): The drain-to-source voltage must equal or exceed 400V to maintain circuit protection margins. Parts rated at higher voltages (such as 550V or 650V) are acceptable for applications where the FDP24N40 operates below its maximum voltage specification.

Current Rating (Id): The continuous drain current must meet or exceed 24A at 25°C to ensure the substitute can handle the same load conditions without thermal stress.

On-State Resistance (Rds On): The maximum on-state resistance determines power dissipation and heat generation. Lower Rds On values indicate improved efficiency and reduced thermal load.

Gate Charge (Qg): Gate charge affects switching speed and driver circuit requirements. Lower gate charge values reduce switching losses and simplify gate drive design.

Package and Mounting: All substitutes must use Through Hole mounting in TO-220 family packages to ensure mechanical and thermal compatibility with existing PCB layouts and heatsinking arrangements.

Operating Temperature Range: The substitute must support the full operating temperature range of -55°C to 150°C (TJ) to maintain reliability across all application conditions.

Parameter Comparison

Parameter	FDP24N40	NTP165N65S3H	SIHP25N40D-E3	STP18N55M5
Manufacturer	onsemi	onsemi	Vishay Siliconix	STMicroelectronics
Drain to Source Voltage (Vdss)	400 V	650 V	400 V	550 V
Current - Continuous Drain (Id) @ 25°C	24 A (Tc)	19 A (Tc)	25 A (Tc)	16 A (Tc)
Rds On (Max) @ Id, Vgs	175 mOhm @ 12A, 10V	165 mOhm @ 9.5A, 10V	170 mOhm @ 13A, 10V	192 mOhm @ 8A, 10V
Gate Charge (Qg) (Max) @ Vgs	60 nC @ 10 V	35 nC @ 10 V	88 nC @ 10 V	31 nC @ 10 V
Power Dissipation (Max)	227 W (Tc)	142 W (Tc)	278 W (Tc)	110 W (Tc)
Operating Temperature Range	-55°C ~ 150°C (TJ)	-55°C ~ 150°C (TJ)	-55°C ~ 150°C (TJ)	-55°C ~ 150°C (TJ)
Package / Case	TO-220-3	TO-220-3	TO-220-3	TO-220-3
Mounting Type	Through Hole	Through Hole	Through Hole	Through Hole
Product Status	Obsolete	Not For New Designs	Active	Active
RoHS Status	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant

Engineering Selection Recommendations

SIHP25N40D-E3 (Vishay Siliconix): This part is the primary substitute for the FDP24N40. It matches the 400V voltage rating exactly and exceeds the current requirement with 25A continuous drain current. The on-state resistance of 170 mOhm is comparable to the original part, and power dissipation capability of 278W exceeds the FDP24N40 specification. The SIHP25N40D-E3 carries Active product status, ensuring long-term availability and supply chain support. All compliance certifications (ROHS3, REACH Unaffected, EAR99) align with the original part. This device is suitable for direct replacement in existing designs.

NTP165N65S3H (onsemi): This part offers higher voltage rating (650V) and lower gate charge (35 nC), providing improved switching efficiency. However, the continuous drain current is reduced to 19A, which is below the FDP24N40 specification of 24A. The NTP165N65S3H is classified as Not For New Designs, limiting its suitability for long-term applications. This part is appropriate only for applications where the 24A current requirement can be reduced or where higher voltage margin is critical.

STP18N55M5 (STMicroelectronics): This part provides 550V voltage rating and significantly lower gate charge (31 nC), supporting faster switching operation. The continuous drain current is limited to 16A, substantially below the FDP24N40 requirement of 24A. Power dissipation capability is reduced to 110W. The STP18N55M5 is classified as Active and carries full compliance certifications. This part is suitable only for applications where current requirements are lower than the original design specification.

Frequently Asked Questions (FAQ)

Q: Can the SIHP25N40D-E3 be used as a direct replacement for the FDP24N40?

A: Yes. The SIHP25N40D-E3 matches the 400V voltage rating, exceeds the 24A current requirement with 25A capability, and maintains comparable on-state resistance. Both devices use TO-220-3 Through Hole packaging and support the full -55°C to 150°C operating temperature range. The SIHP25N40D-E3 is Active status, ensuring supply availability.

Q: Why does the NTP165N65S3H have lower continuous drain current than the FDP24N40?

A: The NTP165N65S3H is designed for higher voltage applications (650V) with optimized characteristics for that voltage class. The reduced current rating reflects the different thermal and electrical design trade-offs inherent to higher voltage MOSFET technology. This part is suitable only for applications where the actual current requirement is 19A or lower.

Q: What is the impact of different gate charge values on circuit design?

A: Gate charge (Qg) determines the energy required to switch the MOSFET on and off. Lower gate charge values (such as 31 nC in the STP18N55M5 or 35 nC in the NTP165N65S3H) reduce switching losses and allow faster switching speeds with lower gate drive power requirements. Higher gate charge values (such as 88 nC in the SIHP25N40D-E3) require more gate drive energy but do not prevent substitution if the gate driver circuit has sufficient capability.

Q: Are all substitute parts RoHS3 compliant?

A: Yes. All substitute parts listed (NTP165N65S3H, SIHP25N40D-E3, and STP18N55M5) are ROHS3 Compliant, matching the compliance status of the FDP24N40. All parts are also REACH Unaffected and classified as EAR99 for export control purposes.

Q: Can I use a higher voltage rated MOSFET in place of the FDP24N40?

A: Yes. MOSFETs rated at higher voltages (550V or 650V) can be used in applications designed for 400V operation. The higher voltage rating provides additional safety margin and protection against voltage transients. However, higher voltage devices typically have increased on-state resistance and gate charge, which may affect power dissipation and switching performance.

Q: What is the difference between TO-220-3 and TO-220AB packaging?

A: Both are Through Hole packages in the TO-220 family with identical pin configurations and thermal characteristics. The designations reflect minor variations in lead forming or supplier specifications but are mechanically and electrically interchangeable for PCB mounting and heatsinking applications.

Q: Why is the FDP24N40 classified as Obsolete?

A: Obsolete status indicates the manufacturer has discontinued production and no longer accepts new orders. This classification necessitates identification of active substitute parts to support existing applications and ensure continued supply chain access for maintenance and repair activities.

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