IXFX66N85X Equivalent & Substitute Parts

Part Overview

The IXFX66N85X is an N-Channel MOSFET manufactured by IXYS, part of the HiPerFET™ Ultra X series. This device is rated for 850V drain-to-source voltage with 66A continuous drain current and 1250W maximum power dissipation in a Through Hole PLUS247™-3 package. The component is Active in product status with full RoHS3 compliance and unlimited moisture sensitivity rating. Substitute parts are identified to provide alternative sourcing options when the primary part is unavailable or when application requirements necessitate alternative electrical characteristics within compatible operating parameters.

Key Parameters

Parameter	Value	Unit
FET Type	N-Channel	—
Drain to Source Voltage (Vdss)	850	V
Current - Continuous Drain (Id) @ 25°C	66	A (Tc)
Rds On (Max) @ Id, Vgs	65	mOhm @ 500mA, 10V
Power Dissipation (Max)	1250	W (Tc)
Operating Temperature Range	-55 to 150	°C (TJ)
Mounting Type	Through Hole	—
Package / Case	TO-247-3 Variant	—
RoHS Status	ROHS3 Compliant	—

Substitute Part Grouping Explanation

Substitution of the IXFX66N85X is determined by the following critical parameters:

Mandatory Compatibility Criteria:

FET Type: N-Channel topology required
Mounting Type: Through Hole configuration
Package / Case: TO-247-3 or compatible variant
RoHS Status: ROHS3 Compliant
Drain to Source Voltage (Vdss): Must meet or exceed 850V application requirement
Current - Continuous Drain (Id): Must support 66A or higher at 25°C
Power Dissipation: Must accommodate thermal requirements of the application

The SCT3040KLGC11 qualifies as a substitute based on these parameters. While it employs SiCFET technology rather than traditional MOSFET technology, it maintains N-Channel configuration, Through Hole mounting, TO-247-3 package compatibility, and ROHS3 compliance. The substitute provides higher voltage rating (1200V vs. 850V) and comparable on-resistance characteristics, enabling direct functional replacement in applications where these electrical parameters are acceptable.

Parameter Comparison

Parameter	IXFX66N85X	SCT3040KLGC11	Unit
Manufacturer	IXYS	Rohm Semiconductor	—
FET Type	N-Channel	N-Channel	—
Technology	MOSFET (Metal Oxide)	SiCFET (Silicon Carbide)	—
Drain to Source Voltage (Vdss)	850	1200	V
Current - Continuous Drain (Id) @ 25°C	66	55	A (Tc)
Rds On (Max) @ Id, Vgs	65 @ 500mA, 10V	52 @ 20A, 18V	mOhm
Vgs(th) (Max) @ Id	5.5 @ 8mA	5.6 @ 10mA	V
Gate Charge (Qg) (Max) @ Vgs	230 @ 10V	107 @ 18V	nC
Power Dissipation (Max)	1250	262	W (Tc)
Operating Temperature (Max)	150	175	°C (TJ)
Mounting Type	Through Hole	Through Hole	—
Package / Case	TO-247-3 Variant	TO-247-3	—
RoHS Status	ROHS3 Compliant	ROHS3 Compliant	—
Product Status	Active	Active	—

Engineering Selection Recommendations

Both the IXFX66N85X and SCT3040KLGC11 maintain Active product status with full ROHS3 compliance and REACH unaffected designation. Selection between these components is determined by application-specific electrical requirements:

IXFX66N85X Selection Criteria:

Applications requiring 850V maximum drain-to-source voltage rating
Systems demanding 66A continuous drain current capacity
Designs utilizing traditional MOSFET technology
Thermal environments where 1250W power dissipation capability is required
Operating conditions within -55°C to 150°C junction temperature range

SCT3040KLGC11 Selection Criteria:

Applications requiring higher voltage margin with 1200V Vdss rating
Systems where 55A continuous drain current is sufficient
Designs benefiting from SiCFET technology characteristics
Thermal environments where 262W power dissipation is adequate
Operating conditions extending to 175°C junction temperature
Applications where reduced gate charge (107 nC vs. 230 nC) provides switching efficiency benefits

Both components are available in production quantities with equivalent packaging and compliance certifications.

Frequently Asked Questions (FAQ)

Q: Can the SCT3040KLGC11 directly replace the IXFX66N85X in existing PCB designs?

A: Physical package compatibility is confirmed (both TO-247-3), and pin configuration is compatible for Through Hole mounting. However, the SCT3040KLGC11 exhibits lower continuous drain current (55A vs. 66A) and reduced power dissipation rating (262W vs. 1250W). Substitution is valid only when application current and thermal requirements do not exceed the SCT3040KLGC11 specifications.

Q: What are the key electrical differences between these components?

A: The IXFX66N85X provides higher continuous current capacity (66A) and significantly higher power dissipation capability (1250W). The SCT3040KLGC11 offers higher voltage rating (1200V vs. 850V), lower gate charge (107 nC vs. 230 nC), and higher maximum junction temperature (175°C vs. 150°C). Technology differs: IXFX66N85X uses traditional MOSFET; SCT3040KLGC11 uses Silicon Carbide FET.

Q: Are both components RoHS3 compliant?

A: Yes. Both the IXFX66N85X and SCT3040KLGC11 are ROHS3 compliant with unlimited moisture sensitivity rating (MSL 1).

Q: What is the significance of the different Rds On specifications?

A: The IXFX66N85X specifies Rds On at 500mA with 10V gate drive (65 mOhm), while the SCT3040KLGC11 specifies Rds On at 20A with 18V gate drive (52 mOhm). These measurements reflect different test conditions and technology characteristics. Direct comparison requires evaluation at identical operating conditions specific to the application.

Q: Can I use the SCT3040KLGC11 in a 66A application?

A: No. The SCT3040KLGC11 is rated for 55A continuous drain current at 25°C. Applications requiring 66A must use the IXFX66N85X or equivalent component with matching current rating.

Q: What packaging format is used for both components?

A: Both components are supplied in Through Hole PLUS247™-3 / TO-247-3 packages in Tube packaging format.

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