IXTH20N65X N-Channel 650V 20A MOSFET Equivalent & Substitute Parts

Part Overview

The IXTH20N65X is an N-Channel 650V 20A MOSFET manufactured by IXYS in the Ultra X series, housed in a TO-247 through-hole package. This device is classified as Last Time Buy, indicating discontinued production with limited inventory availability. The part delivers 320W maximum power dissipation and operates across the industrial temperature range of -55°C to 150°C.

Equivalent and substitute parts are necessary due to the Last Time Buy status of the IXTH20N65X. Identifying compatible alternatives ensures design continuity and supply chain resilience for applications requiring N-Channel high-voltage MOSFETs in the 600V to 800V range with comparable current ratings and thermal performance.

Key Parameters

Parameter	Value	Unit
FET Type	N-Channel	—
Drain to Source Voltage (Vdss)	650	V
Continuous Drain Current (Id) @ 25°C	20	A
On-State Resistance (Rds On) @ 10A, 10V	210	mOhm
Gate Threshold Voltage (Vgs(th)) @ 250µA	5.5	V
Gate Charge (Qg) @ 10V	35	nC
Power Dissipation (Max)	320	W
Operating Temperature Range	-55 to 150	°C
Package Type	TO-247-3	—
Mounting Type	Through Hole	—

Substitute Part Grouping Explanation

Substitution logic for the IXTH20N65X is based on the following criteria:

Primary Substitution Criteria:

Drain to Source Voltage (Vdss): 650V nominal, with tolerance to 800V for higher-rated alternatives
Continuous Drain Current (Id): Minimum 20A at 25°C; higher ratings acceptable
Package Type: TO-247-3 through-hole configuration required
Operating Temperature Range: -55°C to 150°C minimum
On-State Resistance (Rds On): Lower values preferred for improved efficiency; values up to 290mOhm acceptable
Gate Charge (Qg): Lower values reduce switching losses; values up to 177nC acceptable

Substitution Categories:

Direct Manufacturer Upgrade (MFR Recommended): IXTH20N65X2 from IXYS maintains identical voltage and current ratings with improved specifications and Active product status.

Voltage-Rated Alternatives: SPW17N80C3FKSA1, SIHG17N80E-GE3, and STW23N80K5 operate at 800V, providing higher voltage margin. These parts maintain comparable or higher current ratings and are suitable for applications where voltage headroom is beneficial.

Current-Reduced Alternatives: STW18N60M2 operates at 600V with 13A continuous current, representing a lower-current option for applications not requiring the full 20A rating.

All substitute parts maintain TO-247-3 packaging, through-hole mounting, and the -55°C to 150°C operating temperature range.

Parameter Comparison

Parameter	IXTH20N65X	IXTH20N65X2	SPW17N80C3FKSA1	SIHG17N80E-GE3	STW23N80K5	STW18N60M2
Manufacturer	IXYS	IXYS	Infineon	Vishay Siliconix	STMicroelectronics	STMicroelectronics
Vdss (V)	650	650	800	800	800	600
Id @ 25°C (A)	20	20	17	15	16	13
Rds On @ 10V (mOhm)	210	185	290	290	280	280
Vgs(th) @ 250µA (V)	5.5	4.5	3.9	4.0	5.0	4.0
Qg @ 10V (nC)	35	27	177	122	33	21.5
Power Dissipation (W)	320	290	227	208	190	110
Operating Temp (°C)	-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-247-3	TO-247-3
Product Status	Last Time Buy	Active	Active	Active	Active	Active
RoHS Status	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant	Not specified	ROHS3 Compliant	ROHS3 Compliant

Engineering Selection Recommendations

IXTH20N65X2 (MFR Recommended Substitute)

The IXTH20N65X2 is the primary recommended substitute. It maintains identical voltage (650V) and current (20A) ratings while delivering improved electrical performance: lower on-state resistance (185mOhm vs. 210mOhm), reduced gate charge (27nC vs. 35nC), and lower power dissipation (290W vs. 320W). The part carries Active product status with 1040 units in stock, ensuring supply availability. ROHS3 compliance and REACH Unaffected status match the original part's regulatory standing.

SPW17N80C3FKSA1 (Infineon CoolMOS™)

This part operates at 800V with 17A continuous current, providing higher voltage rating and comparable current delivery. The 290mOhm on-state resistance and 227W power dissipation represent acceptable trade-offs for applications benefiting from increased voltage margin. Active product status with 9900 units in stock provides excellent availability. ROHS3 compliance and REACH Unaffected status are confirmed.

STW23N80K5 (STMicroelectronics MDmesh™ K5)

Operating at 800V with 16A continuous current, this part offers higher voltage rating with slightly reduced current capacity. The 280mOhm on-state resistance and 190W power dissipation are suitable for designs where thermal management is less critical. Active product status with 1300 units in stock ensures supply continuity. ROHS3 compliance and REACH Unaffected status are confirmed.

SIHG17N80E-GE3 (Vishay Siliconix)

This 800V, 15A device provides the highest voltage rating among substitutes. The 290mOhm on-state resistance and 208W power dissipation represent acceptable performance for applications requiring maximum voltage headroom. Active product status with 2400 units in stock provides strong availability. Moisture Sensitivity Level 1 (Unlimited) is confirmed.

STW18N60M2 (STMicroelectronics MDmesh™ II Plus)

This part operates at 600V with 13A continuous current, representing a lower-current alternative. The 280mOhm on-state resistance and 110W power dissipation are appropriate for reduced-power applications. Active product status with 1322 units in stock ensures availability. ROHS3 compliance and REACH Unaffected status are confirmed.

Frequently Asked Questions (FAQ)

Q: Can IXTH20N65X2 be used as a direct replacement for IXTH20N65X?

A: Yes. The IXTH20N65X2 maintains identical voltage (650V) and current (20A) ratings with improved specifications. It uses the same TO-247-3 package and operates across the same temperature range (-55°C to 150°C). The lower on-state resistance and gate charge provide performance benefits in existing designs.

Q: What is the primary difference between the IXTH20N65X and higher-voltage substitutes like SPW17N80C3FKSA1?

A: The IXTH20N65X operates at 650V, while SPW17N80C3FKSA1 operates at 800V. The higher voltage rating provides additional margin in applications subject to voltage transients or overshoot conditions. Current ratings differ slightly (20A vs. 17A), which may affect thermal performance in high-current applications.

Q: Is the STW18N60M2 suitable for applications requiring 20A continuous current?

A: No. The STW18N60M2 is rated for 13A continuous current at 25°C, making it unsuitable for designs requiring the full 20A rating of the IXTH20N65X. This part is appropriate only for applications with reduced current requirements.

Q: Do all substitute parts maintain the same package configuration?

A: Yes. All substitute parts listed use the TO-247-3 through-hole package, ensuring mechanical and thermal compatibility with existing PCB layouts and heatsink mounting arrangements.

Q: What is the significance of the Last Time Buy status for IXTH20N65X?

A: Last Time Buy indicates that IXYS has discontinued production of the IXTH20N65X. Current inventory (1327 units) represents the final available stock. Designs should transition to IXTH20N65X2 or alternative substitutes to ensure long-term supply continuity.

Q: Are all substitute parts RoHS3 compliant?

A: IXTH20N65X2, SPW17N80C3FKSA1, STW23N80K5, and STW18N60M2 are confirmed ROHS3 compliant. SIHG17N80E-GE3 RoHS status is not specified in available documentation.

Q: How does on-state resistance (Rds On) affect circuit performance?

A: Lower on-state resistance reduces conduction losses and heat generation during operation. The IXTH20N65X2 (185mOhm) delivers lower losses than the original IXTH20N65X (210mOhm). Higher-voltage alternatives (SPW17N80C3FKSA1, SIHG17N80E-GE3, STW23N80K5) operate at 280–290mOhm, resulting in increased conduction losses but acceptable performance in many applications.

Q: What does gate charge (Qg) represent, and why is it important?

A: Gate charge is the total charge required to switch the MOSFET from off to on state. Lower gate charge reduces switching losses and allows faster switching transitions. The IXTH20N65X2 (27nC) and STW18N60M2 (21.5nC) offer lower gate charge than the original IXTH20N65X (35nC), improving efficiency in high-frequency switching applications.

Q: Can substitute parts with higher voltage ratings (800V) be used in 650V applications?

A: Yes. Parts rated for 800V can operate safely in 650V applications, as the higher voltage rating provides additional safety margin. However, the higher voltage rating typically results in increased on-state resistance and gate charge, which may affect efficiency and switching performance.

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