IRFZ40 N-Channel MOSFET 60V 50A TO-220AB Equivalent & Substitute Parts

Part Overview

The IRFZ40 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. The device is classified as obsolete, necessitating identification of active equivalent and substitute parts for new designs and production applications. Equivalent parts maintain identical electrical and mechanical specifications, while substitute parts provide functional alternatives with minor parameter variations within acceptable operating ranges.

Key Parameters

Parameter	Value	Unit
FET Type	N-Channel	—
Drain to Source Voltage (Vdss)	60	V
Continuous Drain Current (Id) @ 25°C	50	A (Tc)
Rds On (Max) @ Id, Vgs	28	mOhm @ 31A, 10V
Gate Threshold Voltage (Vgs(th)) @ Id	4	V @ 250µA
Gate Charge (Qg) @ Vgs	67	nC @ 10V
Power Dissipation (Max)	150	W (Tc)
Operating Temperature Range	−55 to 175	°C (TJ)
Mounting Type	Through Hole	—
Package / Case	TO-220-3	—

Substitute Part Grouping Explanation

Substitution of the IRFZ40 is determined by equivalence in the following critical parameters: FET type (N-Channel), drain-to-source voltage rating (60V), continuous drain current capability (50A), on-state resistance (Rds On), gate threshold voltage, and through-hole TO-220-3 package configuration. Parts are grouped into two categories:

Direct Equivalents maintain all electrical specifications and differ only in product status (active vs. obsolete) and packaging format (tube vs. bulk). These parts are pin-compatible and electrically interchangeable without circuit modification.

Parametric Equivalents maintain the same voltage rating, package type, and mounting configuration but may exhibit minor variations in continuous drain current, power dissipation, or gate charge within acceptable design tolerances. These parts are functionally compatible for applications where the specified parameter variations do not exceed system requirements.

Parameter Comparison

Parameter	IRFZ40	IRFZ40PBF	IRFZ44PBF	IRFZ44RPBF	STP45NF06
Manufacturer	Vishay Siliconix	Vishay Siliconix	Vishay Siliconix	Vishay Siliconix	STMicroelectronics
Product Status	Obsolete	Active	Active	Active	Active
FET Type	N-Channel	N-Channel	N-Channel	N-Channel	N-Channel
Vdss (V)	60	60	60	60	60
Id @ 25°C (A)	50	50	50	50	38
Rds On (Max) @ Id, Vgs (mOhm)	28 @ 31A, 10V	28 @ 31A, 10V	28 @ 31A, 10V	28 @ 31A, 10V	28 @ 19A, 10V
Vgs(th) @ Id (V)	4 @ 250µA	4 @ 250µA	4 @ 250µA	4 @ 250µA	4 @ 250µA
Qg @ Vgs (nC)	67 @ 10V	67 @ 10V	67 @ 10V	67 @ 10V	58 @ 10V
Power Dissipation (Max) (W)	150	150	150	150	80
Operating Temperature (°C)	−55 to 175	−55 to 175	−55 to 175	−55 to 175	−55 to 175
Package / Case	TO-220-3	TO-220-3	TO-220-3	TO-220-3	TO-220-3
Mounting Type	Through Hole	Through Hole	Through Hole	Through Hole	Through Hole
RoHS Status	Non-compliant	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant

Engineering Selection Recommendations

IRFZ40PBF is the primary direct equivalent for IRFZ40 replacement. This part maintains identical electrical specifications and TO-220-3 package configuration while offering active product status and ROHS3 compliance. The transition from obsolete to active status and improved regulatory compliance make IRFZ40PBF the preferred selection for new designs and production continuity.

IRFZ44PBF and IRFZ44RPBF are parametric equivalents with identical electrical performance to IRFZ40. Both parts are active, ROHS3 compliant, and maintain the same voltage rating, current capability, and package type. The IRFZ44 series designation indicates a product line variant; however, electrical specifications remain equivalent to IRFZ40 specifications. IRFZ44RPBF offers higher inventory availability (5420 units) compared to IRFZ44PBF (1446 units).

STP45NF06 is a manufacturer-recommended substitute from STMicroelectronics. This part operates at the same 60V voltage rating and uses the same TO-220-3 package. The continuous drain current is reduced to 38A (compared to 50A for IRFZ40), and maximum power dissipation is 80W (compared to 150W). STP45NF06 is suitable for applications where the 38A current rating and 80W power dissipation are within system requirements. This part is active and ROHS3 compliant.

Selection between direct equivalents (IRFZ40PBF, IRFZ44PBF, IRFZ44RPBF) should prioritize inventory availability and supply chain stability. Selection of STP45NF06 requires verification that application current and power dissipation requirements do not exceed the reduced specifications.

Frequently Asked Questions (FAQ)

Q: Can IRFZ40PBF be used as a direct replacement for IRFZ40?

A: Yes. IRFZ40PBF maintains identical electrical specifications, gate threshold voltage, on-state resistance, and TO-220-3 package configuration. The parts are pin-compatible and electrically interchangeable. IRFZ40PBF is active and ROHS3 compliant, addressing the obsolete status of IRFZ40.

Q: What is the difference between IRFZ44PBF and IRFZ44RPBF?

A: Both parts maintain identical electrical specifications to IRFZ40 and IRFZ40PBF. The designation difference (PBF vs. RPBF) reflects product line variants within the IRFZ44 series. Electrical performance, voltage rating, current capability, and package type are equivalent. Selection between these parts should be based on inventory availability and supply chain requirements.

Q: Can STP45NF06 replace IRFZ40 in all applications?

A: STP45NF06 is a parametric equivalent suitable for applications where the reduced continuous drain current (38A vs. 50A) and power dissipation (80W vs. 150W) are within system requirements. Applications requiring the full 50A current capability or 150W power dissipation must use IRFZ40PBF, IRFZ44PBF, or IRFZ44RPBF. Voltage rating (60V), gate threshold voltage (4V), and package type (TO-220-3) are equivalent across all parts.

Q: Are all substitute parts ROHS3 compliant?

A: IRFZ40PBF, IRFZ44PBF, IRFZ44RPBF, and STP45NF06 are all ROHS3 compliant. The original IRFZ40 is RoHS non-compliant. Compliance with ROHS3 standards is a key advantage of the active substitute parts for new designs and regulated applications.

Q: What is the significance of the TO-220-3 package for substitution?

A: The TO-220-3 package is a through-hole configuration with three leads (Gate, Drain, Source). All listed substitute parts use the same TO-220-3 package, ensuring mechanical and electrical compatibility without PCB redesign. Package compatibility is a primary criterion for direct substitution in existing circuit designs.

Q: How do gate charge specifications affect substitution?

A: Gate charge (Qg) determines the energy required to switch the MOSFET on and off. IRFZ40, IRFZ40PBF, IRFZ44PBF, and IRFZ44RPBF all specify 67 nC gate charge at 10V. STP45NF06 specifies 58 nC, a 13% reduction. Lower gate charge reduces switching losses and driver circuit stress. Applications with tight switching frequency or driver current constraints may benefit from STP45NF06; however, this parameter difference does not prevent substitution in standard applications.

Q: What inventory considerations apply to part selection?

A: IRFZ40PBF has 10,265 units in stock, IRFZ44RPBF has 5,420 units, IRFZ44PBF has 1,446 units, and STP45NF06 has 8,822 units. For applications requiring immediate availability or high-volume production, IRFZ40PBF and STP45NF06 offer superior inventory positions. IRFZ44RPBF provides a balanced alternative with substantial stock levels.

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