IRFZ44ZPBF N-Channel 55V 51A MOSFET Equivalent & Substitute Parts

Part Overview

The IRFZ44ZPBF is an N-Channel MOSFET manufactured by Infineon Technologies in the HEXFET® series, rated for 55V drain-to-source voltage and 51A continuous drain current at 25°C. The device is packaged in TO-220AB through-hole configuration with 80W maximum power dissipation. The part is designated as "Not For New Designs," indicating it has been superseded in the manufacturer's product line. Equivalent and substitute parts are necessary for applications requiring continued supply, design flexibility, or performance optimization within compatible electrical and mechanical parameters.

Key Parameters

Parameter	Value	Unit
Drain-to-Source Voltage (Vdss)	55	V
Continuous Drain Current (Id) @ 25°C	51	A
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
Operating Temperature Range	-55 to 175	°C
Package Type	TO-220AB	—
Mounting Type	Through Hole	—

Substitute Part Grouping Explanation

Substitution of the IRFZ44ZPBF is determined by the following critical parameters:

Primary Compatibility Criteria:

Drain-to-Source Voltage (Vdss): Must be equal to or greater than 55V
Continuous Drain Current (Id): Must be equal to or greater than 51A at 25°C
Gate Threshold Voltage (Vgs(th)): Must be compatible at 4V nominal
Maximum Gate Voltage (Vgs): Must support ±20V operation
Operating Temperature Range: Must span -55°C to 175°C
Package/Mounting: Through-hole TO-220 family packages (TO-220AB or TO-220-3)

Secondary Compatibility Considerations:

On-State Resistance (Rds On): Lower values indicate improved performance but do not prevent substitution
Gate Charge (Qg): Affects switching speed; higher values acceptable for direct replacement
Power Dissipation: Higher ratings provide thermal margin
RoHS and REACH Compliance: All listed substitutes maintain ROHS3 compliance and REACH unaffected status

Substitute parts are grouped into two categories: Direct Equivalents (matching Vdss and Id specifications) and Enhanced Performance Substitutes (higher current or power ratings within the same voltage class).

Parameter Comparison

Part Number	Manufacturer	Vdss (V)	Id @ 25°C (A)	Rds On (mOhm)	Qg (nC)	Power Diss. (W)	Package	Status
IRFZ44ZPBF	Infineon	55	51	13.9 @ 31A, 10V	43 @ 10V	80	TO-220AB	Not For New Designs
HUF75332P3	onsemi	55	60	19 @ 60A, 10V	85 @ 20V	145	TO-220-3	Active
HUF75339P3	onsemi	55	75	12 @ 75A, 10V	130 @ 20V	200	TO-220-3	Active
HUF75344P3	onsemi	55	75	8 @ 75A, 10V	210 @ 20V	285	TO-220-3	Active
IRFZ44PBF	Vishay Siliconix	60	50	28 @ 31A, 10V	67 @ 10V	150	TO-220AB	Active
IRFZ44RPBF	Vishay Siliconix	60	50	28 @ 31A, 10V	67 @ 10V	150	TO-220AB	Active
IXTP70N075T2	IXYS	75	70	12 @ 25A, 10V	46 @ 10V	150	TO-220-3	Active
PHP191NQ06LT,127	Nexperia USA Inc.	55	75	3.7 @ 25A, 10V	95.6 @ 5V	300	TO-220AB	Obsolete
RFP70N06	onsemi	60	70	14 @ 70A, 10V	156 @ 20V	150	TO-220-3	Active
SQP60N06-15_GE3	Vishay Siliconix	60	56	15 @ 30A, 10V	50 @ 10V	107	TO-220AB	Obsolete
STP45NF06	STMicroelectronics	60	38	28 @ 19A, 10V	58 @ 10V	80	TO-220	Active

Engineering Selection Recommendations

Category 1: Direct Voltage Class Equivalents (55V Rating)

Parts HUF75332P3, HUF75339P3, and HUF75344P3 (onsemi UltraFET™ series) maintain the 55V Vdss specification and exceed the 51A continuous drain current requirement. All three are Active status products with ROHS3 compliance. HUF75344P3 provides the lowest on-state resistance (8 mOhm) and highest power dissipation (285W), offering superior thermal performance. These parts are suitable for direct replacement in applications where the 55V voltage class is specified.

Category 2: Higher Voltage Class Substitutes (60V–75V Rating)

Parts IRFZ44PBF, IRFZ44RPBF (Vishay Siliconix), RFP70N06 (onsemi), and IXTP70N075T2 (IXYS) operate at 60V or 75V Vdss, exceeding the original 55V specification. These parts provide voltage margin and are suitable for applications where higher voltage headroom is acceptable. IRFZ44PBF and IRFZ44RPBF are Active status variants of the same base product family. RFP70N06 and IXTP70N075T2 offer higher current ratings (70A) with Active product status.

Category 3: Obsolete Alternatives

PHP191NQ06LT,127 (Nexperia) and SQP60N06-15_GE3 (Vishay) are designated Obsolete. PHP191NQ06LT,127 maintains 55V Vdss with 75A capability and exceptional on-state resistance (3.7 mOhm). SQP60N06-15_GE3 operates at 60V with 56A rating. These parts should be used only when Active alternatives are unavailable or when existing inventory must be consumed.

Compliance and Certification:

All listed substitutes maintain ROHS3 compliance and REACH unaffected status, matching the original part's regulatory posture. SQP60N06-15_GE3 carries AEC-Q101 automotive qualification, suitable for automotive-grade applications.

Frequently Asked Questions (FAQ)

Q1: Can I use a 60V-rated MOSFET as a direct replacement for the 55V IRFZ44ZPBF?

A: Yes. A 60V-rated device (such as IRFZ44PBF, IRFZ44RPBF, or RFP70N06) is electrically compatible with a 55V application. The higher voltage rating provides additional safety margin and does not degrade performance in circuits designed for 55V operation. Gate drive voltage, threshold voltage, and operating temperature ranges remain compatible.

Q2: What is the difference between HUF75332P3, HUF75339P3, and HUF75344P3?

A: All three maintain 55V Vdss and TO-220-3 packaging. HUF75332P3 is rated for 60A continuous drain current with 19 mOhm on-state resistance. HUF75339P3 and HUF75344P3 both support 75A but differ in on-state resistance: HUF75339P3 has 12 mOhm, while HUF75344P3 has 8 mOhm. The lower on-state resistance in HUF75344P3 reduces conduction losses and heat generation, making it suitable for high-current applications requiring thermal optimization.

Q3: Why is the IRFZ44ZPBF marked "Not For New Designs"?

A: This designation indicates the part has been superseded by newer alternatives in the manufacturer's product line. Existing inventory remains available, but Infineon recommends using current-generation products for new designs. Active alternatives such as HUF75332P3, HUF75339P3, or HUF75344P3 are recommended for new applications.

Q4: Are TO-220AB and TO-220-3 packages interchangeable?

A: Both are through-hole TO-220 family packages with identical pin configurations and mechanical footprints. TO-220AB and TO-220-3 designations refer to the same physical package. PCB layouts and heatsink mounting are compatible between parts using either designation.

Q5: Can I substitute STP45NF06 for the IRFZ44ZPBF?

A: STP45NF06 is not recommended as a direct replacement. Although it operates at 60V (compatible with 55V applications), its continuous drain current rating is 38A, which is below the original 51A specification. Use STP45NF06 only in applications where the actual current requirement does not exceed 38A.

Q6: What is the significance of on-state resistance (Rds On) differences among substitutes?

A: On-state resistance directly affects conduction losses and heat dissipation. Lower Rds On values reduce power loss during operation, resulting in lower junction temperatures and improved efficiency. For example, HUF75344P3 (8 mOhm) dissipates less heat than IRFZ44ZPBF (13.9 mOhm) at the same current level. Higher Rds On values are acceptable for lower-current applications but may require additional thermal management in high-current circuits.

Q7: Should I use PHP191NQ06LT,127 despite its Obsolete status?

A: PHP191NQ06LT,127 should be used only when Active alternatives are unavailable or when consuming existing inventory is a priority. Its Obsolete designation means Nexperia no longer manufactures or supports this part. For new designs or long-term supply assurance, select Active status alternatives such as HUF75344P3 or IXTP70N075T2.

Q8: What gate charge (Qg) differences mean for circuit design?

A: Gate charge affects the energy required to switch the MOSFET on and off. Higher Qg values (such as 210 nC in HUF75344P3 versus 43 nC in IRFZ44ZPBF) require more gate drive current or longer switching times. This impacts switching frequency capability and driver IC selection. For applications with fast switching requirements, lower Qg values are preferable, but higher Qg values do not prevent substitution in standard switching applications.

Q9: Are all listed substitutes RoHS3 compliant?

A: Yes. All substitute parts listed maintain ROHS3 compliance and REACH unaffected status, matching the original IRFZ44ZPBF regulatory requirements. This ensures compatibility with RoHS-regulated markets and supply chains.

Q10: Which substitute offers the best thermal performance?

A: HUF75344P3 provides the highest power dissipation rating (285W) combined with the lowest on-state resistance (8 mOhm @ 75A, 10V). PHP191NQ06LT,127 also offers exceptional thermal performance (300W, 3.7 mOhm @ 25A, 10V) but is Obsolete. For Active products, HUF75344P3 is the optimal choice for thermally demanding applications.

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