IXFK25N90 Equivalent & Substitute Parts

Part Overview

The IXFK25N90 is an N-Channel MOSFET rated for 900V drain-to-source voltage with 25A continuous drain current at 25°C. Manufactured by IXYS under the HiPerFET™ series, this device is packaged in a Through Hole TO-264AA configuration and rated for 560W maximum power dissipation. The part is currently classified as Obsolete, making identification of equivalent and substitute components necessary for ongoing design support, maintenance, and production continuity.

Key Parameters

Parameter	Value	Unit
FET Type	N-Channel	—
Drain to Source Voltage (Vdss)	900	V
Continuous Drain Current (Id) @ 25°C	25	A
Rds On (Max) @ Id, Vgs	330 mOhm @ 500mA, 10V	—
Gate Charge (Qg) (Max) @ Vgs	240	nC @ 10V
Power Dissipation (Max)	560	W
Operating Temperature Range	-55 to 150	°C (TJ)
Mounting Type	Through Hole	—
Package	TO-264AA	—
Product Status	Obsolete	—

Substitute Part Grouping Explanation

Substitution of the IXFK25N90 is determined by the following critical electrical and mechanical parameters:

Voltage Rating Compatibility: The drain-to-source voltage (Vdss) of 900V establishes the maximum voltage the device can withstand. Substitute parts must maintain this 900V rating or higher to ensure safe operation in the original circuit.

Current Capacity: The continuous drain current rating of 25A at 25°C defines the minimum current-handling capability required. Substitute parts with equal or higher current ratings are acceptable, as they provide equivalent or improved performance in this parameter.

On-State Resistance (Rds On): The maximum on-state resistance of 330 mOhm at specified conditions affects power dissipation and thermal performance. Lower Rds On values in substitute parts indicate improved efficiency.

Package and Mounting: The Through Hole TO-264AA package is a mechanical requirement for board compatibility and thermal management. Substitute parts must use the same or compatible package footprint.

Gate Charge and Input Capacitance: These parameters affect switching speed and drive circuit requirements. Substitute parts with comparable or lower values maintain circuit performance characteristics.

Operating Temperature Range: The -55°C to 150°C junction temperature range must be maintained or exceeded in substitute parts to ensure reliability across the intended operating environment.

Parameter Comparison

Parameter	IXFK25N90	IXFK40N90P	FQL40N50F
Manufacturer	IXYS	IXYS	onsemi
FET Type	N-Channel	N-Channel	N-Channel
Drain to Source Voltage (Vdss)	900 V	900 V	500 V
Continuous Drain Current (Id) @ 25°C	25 A	40 A	40 A
Rds On (Max) @ Id, Vgs	330 mOhm @ 500mA, 10V	230 mOhm @ 20A, 10V	110 mOhm @ 20A, 10V
Gate Charge (Qg) (Max) @ Vgs	240 nC @ 10V	230 nC @ 10V	200 nC @ 10V
Power Dissipation (Max)	560 W	960 W	460 W
Operating Temperature Range	-55 to 150 °C (TJ)	-55 to 150 °C (TJ)	-55 to 150 °C (TJ)
Mounting Type	Through Hole	Through Hole	Through Hole
Package	TO-264AA	TO-264AA	TO-264-3
Product Status	Obsolete	Active	Obsolete
Vgs (Max)	±20 V	±30 V	±30 V
Input Capacitance (Ciss) (Max) @ Vds	10800 pF @ 25V	14000 pF @ 25V	7500 pF @ 25V

Engineering Selection Recommendations

IXFK40N90P (Direct Equivalent): This part is the primary substitute for the IXFK25N90. Both devices share the same 900V voltage rating, identical operating temperature range, and compatible TO-264AA package. The IXFK40N90P provides 40A continuous drain current compared to the 25A of the original part, representing a 60% increase in current capacity. The on-state resistance is lower at 230 mOhm, improving efficiency. Critically, the IXFK40N90P maintains Active product status, ensuring long-term availability and supply chain continuity. RoHS3 compliance provides additional environmental and regulatory assurance. This part is suitable for direct substitution in applications where the increased current rating and improved thermal performance are beneficial or neutral to circuit operation.

FQL40N50F (Voltage-Derated Substitute): This onsemi FRFET® device operates at a reduced voltage rating of 500V compared to the 900V specification of the IXFK25N90. The FQL40N50F is suitable only for applications where the circuit voltage does not exceed 500V. This part offers superior on-state resistance at 110 mOhm and lower input capacitance at 7500 pF, both advantageous for efficiency and switching performance. However, the FQL40N50F is classified as Obsolete, limiting its viability for new designs or long-term production support. The package designation TO-264-3 is mechanically compatible with TO-264AA footprints. This substitute is applicable only when voltage derating is acceptable and immediate availability from existing inventory is prioritized.

Frequently Asked Questions (FAQ)

Q: Can the IXFK40N90P be used as a direct replacement for the IXFK25N90?

A: Yes. The IXFK40N90P is a direct substitute. Both parts share identical voltage ratings (900V), operating temperature ranges (-55°C to 150°C), and package types (TO-264AA). The IXFK40N90P provides higher current capacity (40A versus 25A) and lower on-state resistance (230 mOhm versus 330 mOhm), making it functionally superior. The IXFK40N90P is currently in Active product status, ensuring availability.

Q: Why is the FQL40N50F listed as a substitute if it has a lower voltage rating?

A: The FQL40N50F is listed as a similar substitute based on current capacity and package compatibility, not voltage equivalence. This part is suitable only for applications operating at 500V or below. The reduced voltage rating represents a design constraint that must be evaluated against the specific circuit requirements. Use of this part in circuits exceeding 500V will result in device failure.

Q: Are the TO-264AA and TO-264-3 packages interchangeable?

A: The TO-264-3 and TO-264AA packages are mechanically compatible and share the same three-pin through-hole footprint. Both packages are suitable for the same PCB layouts and thermal management approaches. Pin assignments and lead spacing are identical.

Q: What is the significance of the Obsolete product status for the IXFK25N90?

A: Obsolete status indicates that the manufacturer has discontinued production and support for this part. Existing inventory may be available from distributors, but long-term supply cannot be guaranteed. For new designs or production runs requiring extended component availability, the Active-status IXFK40N90P is the recommended choice.

Q: How does the increased current rating of the IXFK40N90P affect circuit design?

A: The higher current rating of the IXFK40N90P (40A versus 25A) does not negatively impact circuit operation. The part will operate safely at the original 25A design current. The increased rating provides design margin and improved thermal performance due to lower on-state resistance, reducing power dissipation and junction temperature in the same application.

Q: What compliance certifications should be considered when selecting a substitute?

A: The IXFK40N90P carries RoHS3 compliance certification, meeting current environmental and hazardous substance restrictions. Both the IXFK25N90 and IXFK40N90P are REACH Unaffected and classified under ECCN EAR99. These certifications ensure regulatory compliance for commercial and industrial applications.

Q: Does the gate charge difference between these parts affect the drive circuit?

A: Gate charge values are comparable across all three parts (240 nC for IXFK25N90, 230 nC for IXFK40N90P, and 200 nC for FQL40N50F). These minor differences do not require drive circuit redesign. Existing gate drive circuits designed for the IXFK25N90 will operate correctly with either substitute part.

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