IXFX34N80 N-Channel 800V 34A MOSFET Equivalent & Substitute Parts

Part Overview

The IXFX34N80 is an N-Channel 800V 34A MOSFET manufactured by IXYS in the HiPerFET™ series, housed in a PLUS247™-3 (TO-247-3 variant) through-hole package. This device is rated for 560W maximum power dissipation at the case temperature and operates across the temperature range of -55°C to 150°C. The part is currently marked as "Not For New Designs," indicating it has reached end-of-life status. Identifying equivalent and substitute parts is necessary for ongoing maintenance, repair, and legacy system support where the original IXFX34N80 is no longer readily available or when design flexibility permits component selection from active product lines.

Key Parameters

Parameter	Value	Unit	Specification Basis
Drain to Source Voltage (Vdss)	800	V	Maximum voltage rating between drain and source
Continuous Drain Current (Id) @ 25°C	34	A (Tc)	Maximum continuous current at case temperature
On-State Resistance (Rds On) @ Id, Vgs	240 mOhm @ 17A, 10V	mOhm	Drain-source on-state resistance at specified conditions
Gate Threshold Voltage (Vgs(th)) @ Id	5	V @ 8mA	Gate voltage required to initiate conduction
Gate Charge (Qg) @ Vgs	270	nC @ 10V	Total gate charge at specified gate voltage
Maximum Gate Voltage (Vgs Max)	±20	V	Absolute maximum gate-source voltage
Input Capacitance (Ciss) @ Vds	7500	pF @ 25V	Input capacitance at specified drain-source voltage
Power Dissipation (Max)	560	W (Tc)	Maximum power dissipation at case temperature
Operating Temperature Range	-55 to 150	°C (TJ)	Junction temperature operating range
Package Type	PLUS247™-3	TO-247-3 Variant	Through-hole surface mount package
FET Type	N-Channel	—	Transistor channel type
Technology	MOSFET (Metal Oxide)	—	Semiconductor technology

Substitute Part Grouping Explanation

Substitution of the IXFX34N80 is determined by strict adherence to the following electrical and mechanical parameters:

Primary Substitution Criteria:

Drain to Source Voltage (Vdss): Must be ≥800V to maintain voltage rating compatibility
Continuous Drain Current (Id): Must be ≥34A to support the same current-handling capacity
On-State Resistance (Rds On): Should be comparable (within engineering tolerance) to minimize thermal and efficiency impacts
Gate Threshold Voltage (Vgs(th)): Must be within ±1V of the original specification to ensure gate drive compatibility
Maximum Gate Voltage (Vgs Max): Must be ≥±20V to accommodate standard gate drive circuits
Operating Temperature Range: Must span -55°C to 150°C minimum
Package Type: Must be through-hole TO-247-3 or compatible variant to ensure mechanical and thermal interface compatibility

Secondary Compatibility Factors:

Gate Charge (Qg) and Input Capacitance (Ciss) influence switching speed and gate drive requirements but do not prevent substitution
Power Dissipation rating should meet or exceed 560W to ensure thermal headroom under identical operating conditions
RoHS3 compliance and REACH status ensure regulatory alignment with modern supply chains

Substitute parts are grouped into two categories:

Category A – Direct Electrical Equivalents (800V, ≥34A): Parts that meet or exceed the primary electrical specifications and maintain the same voltage and current ratings.

Category B – Functional Alternatives (800V, Lower Current or Different Voltage): Parts that operate at the same voltage class but with different current ratings, or parts at different voltage ratings that may be suitable for specific application contexts where voltage derating is acceptable.

Parameter Comparison

Part Number	Manufacturer	Vdss (V)	Id @ 25°C (A)	Rds On (mOhm)	Vgs(th) (V)	Qg (nC)	Vgs Max (±V)	Ciss (pF)	Pd Max (W)	Package	Status
IXFX34N80	IXYS	800	34	240 @ 17A, 10V	5 @ 8mA	270 @ 10V	±20	7500 @ 25V	560	PLUS247™-3	Not For New Designs
IXFX44N80P	IXYS	800	44	190 @ 22A, 10V	5 @ 8mA	198 @ 10V	±30	12000 @ 25V	1040	PLUS247™-3	Active
APT34F60B	Microchip Technology	600	36	210 @ 17A, 10V	5 @ 1mA	165 @ 10V	±30	6640 @ 25V	624	TO-247 [B]	Active
APT38F80B2	Microchip Technology	800	41	240 @ 20A, 10V	5 @ 2.5mA	260 @ 10V	±30	8070 @ 25V	1040	T-MAX™ [B2]	Active
IRFP22N60KPBF	Vishay Siliconix	600	22	280 @ 13A, 10V	5 @ 250µA	150 @ 10V	±30	3570 @ 25V	370	TO-247AC	Active
SPW17N80C3FKSA1	Infineon Technologies	800	17	290 @ 11A, 10V	3.9 @ 1mA	177 @ 10V	±20	2320 @ 25V	227	PG-TO247-3-1	Active
STW18N65M5	STMicroelectronics	650	15	220 @ 7.5A, 10V	5 @ 250µA	31 @ 10V	±25	1240 @ 100V	110	TO-247-3	Active
STW18NM80	STMicroelectronics	800	17	295 @ 8.5A, 10V	5 @ 250µA	70 @ 10V	±30	2070 @ 50V	190	TO-247-3	Active

Engineering Selection Recommendations

Category A – Direct Electrical Equivalents (Recommended for Primary Substitution):

IXFX44N80P (IXYS) – This part is the direct successor within the IXYS HiPerFET™ series. It maintains the same 800V Vdss rating and PLUS247™-3 package, with increased current capacity (44A vs. 34A) and improved on-state resistance (190 mOhm vs. 240 mOhm). The part is in Active product status, ensuring long-term availability. Gate threshold voltage and maximum gate voltage specifications are compatible with standard gate drive circuits. This is the preferred substitute for direct replacement in new procurement.

APT38F80B2 (Microchip Technology) – This part meets the 800V Vdss and exceeds the 34A current requirement (41A rating). It is housed in a T-MAX™ [B2] package, which is mechanically and thermally compatible with TO-247-3 applications. On-state resistance (240 mOhm @ 20A, 10V) is equivalent to the original part. The device is in Active status and carries ROHS3 compliance. Gate specifications (Vgs(th) = 5V @ 2.5mA, Vgs Max = ±30V) are compatible with standard gate drive implementations.

Category B – Functional Alternatives (Conditional Substitution):

SPW17N80C3FKSA1 (Infineon Technologies CoolMOS™) – This part maintains the 800V Vdss rating and TO-247-3 package compatibility. However, the continuous drain current is rated at 17A, which is 50% of the IXFX34N80 specification. This part is suitable only for applications where the actual operating current is ≤17A or where current derating is acceptable. The part is in Active status with high inventory availability (9900 Pcs). Gate threshold voltage is lower (3.9V @ 1mA), which may require gate drive circuit adjustment.

STW18NM80 (STMicroelectronics MDmesh™) – This part provides 800V Vdss in a standard TO-247-3 package with Active product status. The continuous drain current rating is 17A, making it suitable only for applications with reduced current requirements. On-state resistance (295 mOhm @ 8.5A, 10V) is slightly higher than the original. This part is recommended only when current derating is acceptable and thermal management is adequate.

Lower Voltage Alternatives (Not Recommended for Direct Substitution):

APT34F60B (Microchip Technology) and IRFP22N60KPBF (Vishay Siliconix) operate at 600V Vdss, which represents a 25% reduction in voltage rating compared to the IXFX34N80. These parts are suitable only for applications where the actual operating voltage is ≤600V or where voltage derating is explicitly acceptable. Use of these parts in 800V-rated circuits is not recommended.

STW18N65M5 (STMicroelectronics) operates at 650V Vdss with a continuous drain current of only 15A. This part is not suitable as a substitute for the IXFX34N80 due to both voltage and current limitations.

Compliance and Regulatory Considerations:

All recommended substitute parts carry ROHS3 compliance and REACH Unaffected status, ensuring alignment with modern regulatory requirements. The IXFX34N80, while ROHS3 compliant, is marked "Not For New Designs," making active-status alternatives preferable for new procurement and long-term supply chain stability.

Frequently Asked Questions (FAQ)

Q1: Can I use the IXFX44N80P as a direct replacement for the IXFX34N80?

A: Yes. The IXFX44N80P is the recommended direct substitute. Both parts share the same 800V Vdss rating, PLUS247™-3 package, and -55°C to 150°C operating temperature range. The IXFX44N80P has higher current capacity (44A vs. 34A) and lower on-state resistance (190 mOhm vs. 240 mOhm), making it a superior replacement. Gate drive specifications are compatible. The part is in Active status, ensuring availability.

Q2: What is the difference between PLUS247™-3 and T-MAX™ [B2] packages?

A: Both are through-hole TO-247-3 variant packages designed for high-power applications. PLUS247™-3 is IXYS's proprietary designation, while T-MAX™ [B2] is Microchip's equivalent. They are mechanically and thermally compatible for PCB mounting and heatsink attachment. The APT38F80B2 in T-MAX™ [B2] packaging can be used in applications originally designed for PLUS247™-3 devices.

Q3: Why do some substitute parts have lower current ratings (e.g., SPW17N80C3FKSA1 at 17A)?

A: Lower current ratings reflect different die designs and thermal characteristics. The SPW17N80C3FKSA1 is optimized for lower current applications with reduced on-state resistance per ampere. It is suitable only if your application's actual operating current is ≤17A. Using a lower-rated part in a 34A application will result in excessive junction temperature and potential device failure.

Q4: Can I substitute a 600V part (APT34F60B) for the 800V IXFX34N80?

A: Only if your application operates at ≤600V. The 800V rating of the IXFX34N80 provides a 33% voltage margin above 600V operation. Substituting a 600V part eliminates this margin and increases the risk of voltage overstress during transient conditions. Use 600V alternatives only when the actual circuit voltage is confirmed to be ≤600V and transient overvoltage is controlled.

Q5: What is the significance of gate threshold voltage (Vgs(th)) differences?

A: Gate threshold voltage determines the gate voltage required to initiate conduction. The IXFX34N80 specifies Vgs(th) = 5V @ 8mA. Substitute parts with lower Vgs(th) (e.g., SPW17N80C3FKSA1 at 3.9V) may turn on at lower gate voltages, potentially affecting switching timing. Higher Vgs(th) values require higher gate drive voltage. Verify that your gate drive circuit can accommodate the Vgs(th) of the selected substitute.

Q6: How do I evaluate on-state resistance (Rds On) differences?

A: On-state resistance directly affects power dissipation and heat generation. The IXFX34N80 specifies 240 mOhm @ 17A, 10V. The IXFX44N80P specifies 190 mOhm @ 22A, 10V, which is lower and more efficient. Higher Rds On values (e.g., SPW17N80C3FKSA1 at 290 mOhm) increase power dissipation. Calculate power loss (P = I²R) for your actual operating current to determine if thermal management is adequate.

Q7: What does "Not For New Designs" mean for the IXFX34N80?

A: This designation indicates the part has reached end-of-life and is no longer recommended for new product development. Existing inventory may be available, but long-term supply is not guaranteed. For new designs or ongoing production, select from Active-status alternatives such as IXFX44N80P, APT38F80B2, or other parts listed in this reference.

Q8: Are there any gate drive circuit modifications needed when switching to a substitute part?

A: Gate drive modifications depend on the specific substitute. Compare the Vgs(th), Vgs Max, and gate charge (Qg) specifications. If Vgs(th) differs by >1V or Vgs Max is lower than your gate drive voltage, circuit adjustment may be required. Gate charge affects switching speed; higher Qg requires higher gate drive current. Consult the substitute part's datasheet and perform gate drive simulation or bench testing before production deployment.

Q9: Which substitute part has the best thermal performance?

A: The IXFX44N80P has the highest power dissipation rating (1040W vs. 560W for the original), indicating superior thermal capability. The APT38F80B2 also rates 1040W. Both are suitable for high-power applications. Lower-rated parts (SPW17N80C3FKSA1 at 227W, STW18NM80 at 190W) are suitable only for reduced-power applications.

Q10: Can I use multiple lower-current parts in parallel to replace the IXFX34N80?

A: Parallel operation of MOSFETs is possible but requires careful design to ensure current sharing and thermal balance. This approach is not recommended as a simple substitute strategy. Consult MOSFET parallel operation guidelines and perform detailed circuit analysis before implementing parallel configurations.

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