IRLZ44 N-Channel 60V 50A MOSFET Equivalent & Substitute Parts

Part Overview

The IRLZ44 is an N-Channel metal oxide semiconductor field-effect transistor (MOSFET) manufactured by Vishay Siliconix, rated for 60V drain-to-source voltage and 50A continuous drain current in a Through Hole TO-220AB package. This device is classified as Obsolete, indicating it has been discontinued from active production. Due to its obsolete status and limited availability for new designs, equivalent and substitute parts from active manufacturers are necessary to maintain design continuity and ensure long-term supply chain reliability.

Key Parameters

Parameter	Value	Unit
Drain to Source Voltage (Vdss)	60	V
Continuous Drain Current (Id) @ 25°C	50	A (Tc)
On-State Resistance (Rds On) @ 31A, 5V	28	mOhm
Gate Threshold Voltage (Vgs(th)) @ 250µA	2	V
Gate Charge (Qg) @ 5V	66	nC
Power Dissipation (Max)	150	W (Tc)
Operating Temperature Range	-55 to 175	°C (TJ)
Package Type	TO-220AB	Through Hole
FET Type	N-Channel
Technology	MOSFET (Metal Oxide)

Substitute Part Grouping Explanation

Substitution of the IRLZ44 is determined by strict adherence to the following electrical and mechanical parameters:

Primary Substitution Criteria:

Drain to Source Voltage (Vdss): Must equal or exceed 60V
Continuous Drain Current (Id): Must equal or exceed 50A at 25°C
Package Type: Must be Through Hole TO-220 variant (TO-220AB or TO-220-3)
FET Type: Must be N-Channel
Technology: Must be MOSFET (Metal Oxide)

Secondary Compatibility Parameters:

On-State Resistance (Rds On): Lower values indicate improved performance; values at or below 28mOhm are preferred
Gate Threshold Voltage (Vgs(th)): Must be compatible with existing gate drive circuits
Operating Temperature Range: Must support -55°C to 175°C minimum
Power Dissipation: Must support thermal requirements of the application

Substitute parts are grouped into two categories: Direct Equivalents (identical electrical specifications and packaging) and Functional Equivalents (meet or exceed all critical parameters with potential variations in secondary characteristics).

Parameter Comparison

Part Number	Manufacturer	Vdss (V)	Id @ 25°C (A)	Rds On (mOhm)	Vgs(th) (V)	Qg (nC)	Pd Max (W)	Tj Range (°C)	Package	Status
IRLZ44	Vishay Siliconix	60	50	28 @ 31A, 5V	2 @ 250µA	66 @ 5V	150	-55 to 175	TO-220AB	Obsolete
IRLZ44PBF	Vishay Siliconix	60	50	28 @ 31A, 5V	2 @ 250µA	66 @ 5V	150	-55 to 175	TO-220AB	Active
IRLZ44NPBF	Infineon Technologies	55	47	22 @ 25A, 10V	2 @ 250µA	48 @ 5V	110	-55 to 175	TO-220AB	Active
IRFZ44EPBF	Infineon Technologies	60	48	23 @ 29A, 10V	4 @ 250µA	60 @ 10V	110	-55 to 175	TO-220AB	Not For New Designs
STP55NF06L	STMicroelectronics	60	55	18 @ 27.5A, 10V	1.7 @ 250µA	37 @ 4.5V	95	-55 to 175	TO-220	Active
STP45NF06	STMicroelectronics	60	38	28 @ 19A, 10V	4 @ 250µA	58 @ 10V	80	-55 to 175	TO-220	Active
FDP55N06	onsemi	60	55	22 @ 27.5A, 10V	4 @ 250µA	37 @ 10V	114	-55 to 150	TO-220-3	Obsolete
HUF76423P3	onsemi	60	35	30 @ 35A, 10V	3 @ 250µA	34 @ 10V	85	-55 to 175	TO-220-3	Active
NDP6060	onsemi	60	48	25 @ 24A, 10V	4 @ 250µA	70 @ 10V	100	-65 to 175	TO-220-3	Active
RFP50N06	Harris Corporation	60	50	22 @ 50A, 10V	4 @ 250µA	150 @ 20V	131	-55 to 175	TO-220-3	Obsolete

Engineering Selection Recommendations

Tier 1: Direct Equivalent (Recommended for Immediate Replacement)

IRLZ44PBF is the primary recommended substitute. Manufactured by Vishay Siliconix, this part is electrically and mechanically identical to the IRLZ44 with identical electrical specifications across all parameters. The critical distinction is product status: IRLZ44PBF is Active and ROHS3 Compliant, ensuring long-term availability and regulatory compliance. Inventory availability is 2710 units. This part requires no circuit redesign and provides pin-for-pin compatibility in TO-220AB packaging.

Tier 2: Functional Equivalents (Suitable for New Designs)

STP55NF06L (STMicroelectronics) meets or exceeds all critical electrical parameters with 60V Vdss and 55A Id rating. This part demonstrates superior on-state resistance (18mOhm versus 28mOhm) and lower gate charge (37nC versus 66nC), resulting in improved switching efficiency. Product status is Active with ROHS3 Compliance. Operating temperature range matches the IRLZ44 (-55°C to 175°C). Package is TO-220 (compatible with TO-220AB footprints). Inventory is 15465 units.

IRLZ44NPBF (Infineon Technologies) is Active with ROHS3 Compliance. Vdss is 55V (5V lower than IRLZ44) and Id is 47A (3A lower than IRLZ44). This part is suitable only for applications where 55V and 47A ratings are sufficient. On-state resistance is superior at 22mOhm. Inventory is 53100 units, indicating strong availability.

NDP6060 (onsemi) provides 60V Vdss and 48A Id with Active status and ROHS3 Compliance. On-state resistance is 25mOhm. Operating temperature range extends to -65°C minimum. Inventory is 1673 units.

Tier 3: Partial Equivalents (Limited Suitability)

STP45NF06 (STMicroelectronics) has reduced continuous drain current (38A versus 50A) and is suitable only for applications with lower current requirements. Power dissipation is reduced to 80W. Product status is Active with ROHS3 Compliance.

HUF76423P3 (onsemi) has reduced continuous drain current (35A versus 50A) and is suitable only for applications with significantly lower current requirements. Product status is Active with ROHS3 Compliance.

Compliance and Regulatory Status:

All recommended substitutes are ROHS3 Compliant except RFP50N06 (Obsolete, RoHS non-compliant). REACH status is Unaffected for all parts except IRLZ44PBF (REACH Affected). All parts carry ECCN classification EAR99 and HTSUS code 8541.29.0095.

Frequently Asked Questions (FAQ)

Q: Can IRLZ44PBF be used as a direct replacement for IRLZ44?

A: Yes. IRLZ44PBF is electrically and mechanically identical to IRLZ44 with identical specifications for Vdss (60V), Id (50A), Rds On (28mOhm), and all other parameters. The primary difference is product status: IRLZ44PBF is Active and ROHS3 Compliant, whereas IRLZ44 is Obsolete. No circuit modifications are required. Pin configuration and TO-220AB package are identical.

Q: What is the difference between TO-220AB and TO-220-3 packages?

A: Both are Through Hole packages with three leads (Gate, Drain, Source) and are mechanically compatible with standard TO-220 footprints. TO-220AB and TO-220-3 designations refer to the same physical package format. Parts specified as either package type are interchangeable from a mechanical and thermal perspective.

Q: Why does STP55NF06L have lower gate charge (37nC) compared to IRLZ44 (66nC)?

A: Gate charge is determined by the internal capacitance of the MOSFET die and is a function of manufacturing process and die design. Lower gate charge indicates faster switching speed and reduced gate drive power requirements. STP55NF06L's lower gate charge (37nC at 4.5V) compared to IRLZ44 (66nC at 5V) reflects differences in semiconductor process technology. This is a performance advantage in switching applications.

Q: Can IRLZ44NPBF be used in place of IRLZ44 if the application requires 50A continuous current?

A: No. IRLZ44NPBF is rated for 47A continuous drain current, which is 3A below the IRLZ44 specification of 50A. Using IRLZ44NPBF in an application requiring 50A continuous current would exceed the device rating and risk thermal failure. IRLZ44NPBF is suitable only for applications with maximum continuous current of 47A or less.

Q: What is the significance of the Vgs(th) difference between IRLZ44 (2V) and IRFZ44EPBF (4V)?

A: Gate threshold voltage (Vgs(th)) is the minimum gate-to-source voltage required to turn the MOSFET on. IRLZ44 has Vgs(th) of 2V, while IRFZ44EPBF has 4V. This difference affects gate drive circuit design. If the existing gate drive circuit is designed for 2V threshold, IRFZ44EPBF may require circuit modification to ensure adequate gate drive voltage. Verify gate drive voltage compatibility before substitution.

Q: Is RFP50N06 a suitable substitute despite being Obsolete?

A: RFP50N06 meets the electrical specifications (60V Vdss, 50A Id) but is classified as Obsolete and RoHS non-compliant. While electrically equivalent, its obsolete status means limited future availability and potential regulatory compliance issues in new designs. RFP50N06 is not recommended for new designs. Use IRLZ44PBF or STP55NF06L instead.

Q: How does power dissipation rating affect part selection?

A: Power dissipation (Pd) rating indicates the maximum thermal power the device can safely dissipate. IRLZ44 is rated for 150W (Tc). Substitutes with lower Pd ratings (such as STP45NF06 at 80W or HUF76423P3 at 85W) may require enhanced thermal management or are suitable only for lower-power applications. Verify that the substitute's Pd rating meets or exceeds the thermal requirements of your application.

Q: What does "Not For New Designs" status mean for IRFZ44EPBF?

A: "Not For New Designs" indicates that while the part is still available, the manufacturer recommends against using it in new circuit designs. This status typically precedes obsolescence. IRFZ44EPBF should be used only for maintenance or repair of existing equipment. For new designs, select from Active status parts such as IRLZ44PBF, STP55NF06L, or NDP6060.

Q: Can I use STP45NF06 if my application requires 50A continuous current?

A: No. STP45NF06 is rated for 38A continuous drain current, which is 12A below the 50A requirement. This part is suitable only for applications with maximum continuous current of 38A or less. For 50A applications, use IRLZ44PBF, STP55NF06L, or RFP50N06.

Q: What is the impact of lower Rds On values in substitute parts?

A: On-state resistance (Rds On) determines the voltage drop across the MOSFET when conducting. Lower Rds On values result in lower power dissipation and reduced heat generation. For example, STP55NF06L has Rds On of 18mOhm compared to IRLZ44's 28mOhm. This 10mOhm reduction improves efficiency, particularly in high-current applications. Lower Rds On is a performance advantage and does not affect compatibility.

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