AUIRFZ44Z N-Channel MOSFET 55V 51A TO-220 Equivalent & Substitute Parts

Part Overview

The AUIRFZ44Z is an N-Channel MOSFET manufactured by Infineon Technologies, rated for 55V drain-to-source voltage and 51A continuous drain current in a Through Hole TO-220 package. This device is classified as Obsolete, making equivalent and substitute parts necessary for ongoing design support and production continuity. The HEXFET® series component operates across a temperature range of -55°C to 175°C and dissipates up to 80W at the case temperature.

Key Parameters

Parameter	Value	Unit
Drain to Source Voltage (Vdss)	55	V
Continuous Drain Current (Id) @ 25°C	51	A (Tc)
On-State Resistance (Rds On) @ 31A, 10V	13.9	mOhm
Gate Threshold Voltage (Vgs(th)) @ 250µA	4	V
Gate Charge (Qg) @ 10V	43	nC
Power Dissipation (Max)	80	W (Tc)
Operating Temperature Range	-55 to 175	°C (TJ)
Package Type	TO-220-3	Through Hole
RoHS Status	ROHS3 Compliant

Substitute Part Grouping Explanation

Substitution of the AUIRFZ44Z is determined by the following critical electrical and mechanical parameters:

Primary Substitution Criteria:

Drain-to-Source Voltage (Vdss): Must equal or exceed 55V
Continuous Drain Current (Id): Must equal or exceed 51A at 25°C
Gate Threshold Voltage (Vgs(th)): Must be compatible at 4V nominal
Package Type: Must be Through Hole TO-220 or TO-220-3 configuration
Operating Temperature Range: Must support -55°C to 175°C minimum
RoHS Compliance: Must maintain ROHS3 Compliant status

Secondary Compatibility Parameters:

On-State Resistance (Rds On): Lower values indicate improved performance
Gate Charge (Qg): Lower values reduce switching losses
Power Dissipation: Higher ratings provide thermal margin
Maximum Gate Voltage (Vgs Max): Must accommodate ±20V drive signals

The substitute parts listed below meet or exceed these criteria within the allowed electrical and mechanical specifications for N-Channel MOSFET devices in this voltage and current class.

Parameter Comparison

Parameter	AUIRFZ44Z (Main)	STP60NF06L	HUF75339P3	IXTP70N075T2	STP55NF06
Manufacturer	Infineon	STMicroelectronics	onsemi	IXYS	STMicroelectronics
Vdss (V)	55	60	55	75	60
Id @ 25°C (A)	51	60	75	70	50
Rds On @ 10V (mOhm)	13.9 @ 31A	14 @ 30A	12 @ 75A	12 @ 25A	18 @ 27.5A
Vgs(th) @ 250µA (V)	4	1	4	4	4
Qg @ Vgs (nC)	43 @ 10V	66 @ 4.5V	130 @ 20V	46 @ 10V	60 @ 10V
Power Dissipation (W)	80	110	200	150	110
Operating Temp (°C)	-55 to 175	-65 to 175	-55 to 175	-55 to 175	-55 to 175
Package	TO-220-3	TO-220	TO-220-3	TO-220-3	TO-220-3
Product Status	Obsolete	Active	Active	Active	Active
RoHS Status	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant

Engineering Selection Recommendations

STP60NF06L (STMicroelectronics)

This substitute meets the minimum electrical requirements with Vdss of 60V and Id of 60A, exceeding the AUIRFZ44Z specifications. The device maintains ROHS3 compliance and Active product status. On-state resistance of 14mOhm at 30A is comparable to the original part. Power dissipation rating of 110W provides thermal margin. The STripFET™ II series offers extended lower temperature operation to -65°C. This part is suitable for direct replacement in applications where the higher voltage rating and current capacity do not create design conflicts.

HUF75339P3 (onsemi)

This substitute is designated as a Manufacturer Recommended part. It matches the original Vdss of 55V while providing significantly higher continuous drain current of 75A and power dissipation of 200W. The UltraFET™ series device maintains identical gate threshold voltage of 4V and maximum gate voltage of ±20V. ROHS3 compliance and Active product status are confirmed. The higher current and power ratings make this part suitable for applications requiring thermal or current margin improvements over the original design.

IXTP70N075T2 (IXYS)

This substitute is designated as a Manufacturer Recommended part. It provides higher Vdss of 75V and Id of 70A with power dissipation of 150W. The TrenchT2™ series device maintains gate threshold voltage of 4V and maximum gate voltage of ±20V. On-state resistance of 12mOhm at 25A is superior to the original part. ROHS3 compliance and Active product status are confirmed. This part is suitable for applications requiring higher voltage headroom or improved thermal performance.

STP55NF06 (STMicroelectronics)

This substitute provides Vdss of 60V and Id of 50A, closely matching the original current rating. The STripFET™ II series device maintains gate threshold voltage of 4V and maximum gate voltage of ±20V. Power dissipation of 110W exceeds the original specification. ROHS3 compliance and Active product status are confirmed. On-state resistance of 18mOhm at 27.5A is higher than the original part. This substitute is suitable for applications where voltage margin is acceptable and cost optimization is a consideration.

All substitute parts maintain Through Hole mounting in TO-220 or TO-220-3 packages, ensuring mechanical compatibility with existing PCB designs. All parts are ROHS3 compliant and carry Active product status, ensuring long-term availability and supply chain stability.

Frequently Asked Questions (FAQ)

Q: Can the STP60NF06L directly replace the AUIRFZ44Z in all applications?

A: The STP60NF06L meets the minimum electrical requirements with higher Vdss (60V vs 55V) and Id (60A vs 51A). Direct replacement is possible in applications where the higher voltage rating does not create design conflicts. Verify that gate drive circuitry is compatible with the lower gate threshold voltage of 1V versus the original 4V.

Q: What is the primary advantage of the HUF75339P3 substitute?

A: The HUF75339P3 provides the same Vdss as the original part (55V) while offering significantly higher continuous drain current (75A vs 51A) and power dissipation (200W vs 80W). This makes it suitable for applications requiring thermal margin or higher current capacity without redesign.

Q: Are all substitute parts available in the same TO-220 package?

A: All substitute parts are available in Through Hole TO-220 or TO-220-3 packages. The mechanical pin configuration is compatible with standard TO-220 PCB footprints. Verify specific package variant (TO-220 vs TO-220-3) against your PCB design requirements.

Q: Do the substitute parts maintain the same operating temperature range?

A: All substitute parts support the -55°C to 175°C operating temperature range of the original AUIRFZ44Z. The STP60NF06L extends the lower temperature limit to -65°C, providing additional thermal margin in cold environments.

Q: What is the impact of different gate threshold voltages on circuit design?

A: The STP60NF06L has a gate threshold voltage of 1V compared to the original 4V. This lower threshold may affect gate drive timing and switching characteristics. Verify that existing gate drive circuitry provides adequate voltage margin above the threshold voltage for reliable operation.

Q: Are all substitute parts RoHS compliant?

A: All substitute parts listed are ROHS3 compliant, matching the compliance status of the original AUIRFZ44Z. All parts carry REACH Unaffected status and EAR99 export classification.

Q: Which substitute part offers the best on-state resistance performance?

A: The HUF75339P3 and IXTP70N075T2 both provide 12mOhm on-state resistance, superior to the original 13.9mOhm. Lower on-state resistance reduces conduction losses and heat generation in high-current applications.

Q: Can I use the IXTP70N075T2 in a 55V circuit design?

A: Yes. The IXTP70N075T2 has a Vdss rating of 75V, which exceeds the 55V requirement. The higher voltage rating provides additional safety margin and does not create compatibility issues in 55V circuit designs.

Q: What inventory considerations should I evaluate?

A: The STP55NF06 has the highest inventory availability (155,400 pcs), followed by HUF75339P3 (28,300 pcs), STP60NF06L (2,716 pcs), and IXTP70N075T2 (963 pcs). Inventory levels may influence supply chain decisions for high-volume production.

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