IXTH12N90 Equivalent & Substitute Parts

Part Overview

The IXTH12N90 is an N-Channel 900V 12A MOSFET manufactured by IXYS in the TO-247 package. This device is part of the MegaMOS™ series and is classified as obsolete. The part delivers 300W maximum power dissipation and operates across a temperature range of -55°C to 150°C. Due to its obsolete status, equivalent and substitute parts from active manufacturers are necessary for new designs and ongoing production requirements.

Key Parameters

Parameter	Value	Unit
Drain to Source Voltage (Vdss)	900	V
Continuous Drain Current (Id) @ 25°C	12	A
Rds On (Max) @ Id, Vgs	900 mOhm @ 6A, 10V	mOhm
Gate Charge (Qg) @ Vgs	170	nC @ 10V
Power Dissipation (Max)	300	W
Operating Temperature Range	-55 to 150	°C
Package Type	TO-247-3	Through Hole
Vgs (Max)	±20	V
Input Capacitance (Ciss) @ Vds	4500	pF @ 25V

Substitute Part Grouping Explanation

Substitution of the IXTH12N90 is determined by the following critical parameters:

Primary Matching Criteria:

Drain to Source Voltage (Vdss): 900V minimum
Continuous Drain Current (Id): 12A or greater
Package Type: TO-247 or compatible through-hole package
Operating Temperature Range: -55°C to 150°C
Power Dissipation: 300W or greater

Secondary Compatibility Factors:

Gate Charge (Qg): Lower values reduce switching losses
Rds On: Lower on-resistance improves efficiency
Input Capacitance (Ciss): Affects gate drive requirements
Vgs (Max): Gate voltage rating compatibility

Substitute parts are grouped based on their ability to meet or exceed the primary matching criteria while maintaining electrical and thermal performance within acceptable operating margins.

Parameter Comparison

Parameter	IXTH12N90	STW12NK90Z	STW11NK90Z	STW9NK90Z	FQA11N90-F109	STW10N95K5	IRFPF50
Manufacturer	IXYS	STMicroelectronics	STMicroelectronics	STMicroelectronics	onsemi	STMicroelectronics	Vishay Siliconix
Vdss (V)	900	900	900	900	900	950	900
Id @ 25°C (A)	12	11	9.2	8	11.4	8	6.7
Rds On (mOhm)	900 @ 6A, 10V	880 @ 5.5A, 10V	980 @ 4.6A, 10V	1300 @ 3.6A, 10V	960 @ 5.7A, 10V	800 @ 4A, 10V	1600 @ 4A, 10V
Qg (nC)	170 @ 10V	152 @ 10V	115 @ 10V	72 @ 10V	94 @ 10V	22 @ 10V	200 @ 10V
Power Dissipation (W)	300	230	200	160	300	130	190
Operating Temp (°C)	-55 to 150	-55 to 150	-55 to 150	-55 to 150	-55 to 150	-55 to 150	-55 to 150
Package	TO-247-3	TO-247-3	TO-247-3	TO-247-3	TO-3P-3	TO-247-3	TO-247-3
Vgs (Max) (V)	±20	±30	±30	±30	±30	±30	±20
Ciss (pF)	4500 @ 25V	3500 @ 25V	3000 @ 25V	2115 @ 25V	3500 @ 25V	630 @ 100V	2900 @ 25V
Product Status	Obsolete	Active	Active	Active	Active	Active	Active
RoHS Status	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant	RoHS Non-Compliant

Engineering Selection Recommendations

Primary Substitute: STW12NK90Z

The STW12NK90Z from STMicroelectronics is the closest functional equivalent to the IXTH12N90. It matches the 900V voltage rating and provides 11A continuous drain current, which is within 92% of the original specification. The part is active in production, ROHS3 compliant, and available in the standard TO-247-3 package. Power dissipation is rated at 230W, which is lower than the original but sufficient for most applications operating within the original thermal envelope. Gate charge is reduced to 152 nC, providing improved switching performance.

Secondary Substitute: FQA11N90-F109

The FQA11N90-F109 from onsemi provides equivalent voltage and current ratings (900V, 11.4A) with matching 300W power dissipation. This part is active and ROHS3 compliant. The package is TO-3PN (SC-65-3), which differs from the original TO-247-3 but maintains through-hole mounting compatibility. Gate charge is lower at 94 nC. This option is suitable when the TO-3PN package footprint is acceptable.

Alternative Substitute: STW11NK90Z

The STW11NK90Z provides 900V and 9.2A continuous drain current with 200W power dissipation. This part is active, ROHS3 compliant, and uses the TO-247-3 package. It is suitable for applications where the current requirement can be reduced to 9.2A or lower.

Lower Current Alternative: STW9NK90Z

The STW9NK90Z is rated for 900V and 8A continuous drain current with 160W power dissipation. This part is active, ROHS3 compliant, and available in TO-247-3 package. It is applicable only when the design current requirement does not exceed 8A.

Not Recommended: IRFPF50

The IRFPF50 from Vishay Siliconix is not recommended as a substitute. Although it matches the 900V voltage rating and TO-247-3 package, the continuous drain current is only 6.7A, which is significantly below the original 12A specification. Additionally, this part is RoHS non-compliant, which may conflict with regulatory requirements for new designs.

Not Recommended: STW10N95K5

The STW10N95K5 from STMicroelectronics has a higher voltage rating (950V) and lower current rating (8A) compared to the original specification. While it is active and ROHS3 compliant, the reduced current capacity and higher voltage rating make it unsuitable for direct substitution in applications designed for the IXTH12N90.

Frequently Asked Questions (FAQ)

Q: Can the STW12NK90Z directly replace the IXTH12N90 in existing PCB designs?

A: Yes, the STW12NK90Z is pin-compatible with the IXTH12N90 in TO-247-3 package applications. Both parts use the same three-pin through-hole configuration (Gate, Drain, Source). No PCB modifications are required for package compatibility.

Q: What is the significance of the lower power dissipation rating in STW12NK90Z (230W vs. 300W)?

A: The power dissipation rating indicates the maximum thermal power the device can handle under specified conditions. The STW12NK90Z's 230W rating is lower than the original 300W. Applications must verify that actual power dissipation in the circuit does not exceed 230W. In many practical applications, actual dissipation is significantly below the maximum rating, making this substitution viable.

Q: Why is the FQA11N90-F109 in a different package (TO-3PN) than the original?

A: The FQA11N90-F109 uses the TO-3PN package instead of TO-247-3. While both are through-hole packages, they have different physical dimensions and pin configurations. PCB redesign is required to accommodate this package change. This option is suitable only when board layout modifications are feasible.

Q: How does gate charge affect circuit performance?

A: Gate charge (Qg) determines the amount of charge required to switch the MOSFET on and off. Lower gate charge reduces switching losses and allows faster switching speeds with lower gate drive current requirements. The substitute parts generally have lower gate charge values, which can improve overall circuit efficiency.

Q: Is the IRFPF50 suitable for applications requiring 12A continuous current?

A: No. The IRFPF50 is rated for only 6.7A continuous drain current, which is insufficient for applications designed for the IXTH12N90's 12A specification. Using this part would result in device overstress and potential failure.

Q: What does ROHS3 compliance mean for component selection?

A: ROHS3 compliance indicates the part meets Restriction of Hazardous Substances Directive requirements, restricting the use of specific hazardous materials. For new designs and applications subject to regulatory compliance, ROHS3 compliant parts are required. The IRFPF50 is RoHS non-compliant and should not be used in regulated applications.

Q: Can I use STW9NK90Z or STW11NK90Z if my application only requires 8A or 9.2A?

A: Yes, if your circuit design operates at or below these current ratings, these parts are suitable substitutes. Both are active, ROHS3 compliant, and available in the standard TO-247-3 package. Verify that the reduced power dissipation ratings (160W and 200W respectively) are adequate for your thermal requirements.

Q: What is the difference between Vdss and Vgs ratings?

A: Vdss (Drain to Source Voltage) is the maximum voltage that can be applied between the drain and source terminals. Vgs (Gate to Source Voltage) is the maximum voltage that can be applied to the gate terminal. Both ratings must be respected to prevent device damage. The substitute parts have higher Vgs ratings (±30V vs. ±20V), providing greater gate voltage margin.

Q: Are there any thermal considerations when substituting these parts?

A: Yes. The substitute parts have lower maximum power dissipation ratings than the original. Ensure that the thermal design of your application (heatsink, thermal interface, PCB copper area) is adequate for the substitute part's power dissipation limit. Thermal analysis should be performed to confirm safe operation.

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