IRF840AL MOSFET N-Channel 500V 8A Equivalent & Substitute Parts

Part Overview

The IRF840AL is an N-Channel MOSFET manufactured by Vishay Siliconix, rated for 500V drain-to-source voltage with 8A continuous drain current. This device is packaged in a through-hole I2PAK (TO-262-3) configuration and is designed for high-voltage switching applications. The IRF840AL carries an obsolete product status, making identification of functionally equivalent alternatives necessary for ongoing design support, maintenance, and production continuity.

Key Parameters

Parameter	Value	Unit
FET Type	N-Channel	—
Drain to Source Voltage (Vdss)	500	V
Continuous Drain Current (Id) @ 25°C	8	A (Tc)
Drive Voltage (Max Rds On)	10	V
Rds On (Max) @ Id, Vgs	850	mOhm @ 4.8A, 10V
Gate Threshold Voltage Vgs(th) (Max) @ Id	4	V @ 250µA
Gate Charge (Qg) (Max) @ Vgs	38	nC @ 10V
Gate Voltage (Vgs) Max	±30	V
Input Capacitance (Ciss) (Max) @ Vds	1018	pF @ 25V
Power Dissipation (Max)	3.1 (Ta), 125 (Tc)	W
Operating Temperature Range	-55 to 150	°C (TJ)
Mounting Type	Through Hole	—
Package / Case	TO-262-3 Long Leads, I2PAK, TO-262AA	—

Substitute Part Grouping Explanation

Substitution of the IRF840AL is determined by strict equivalence across electrical and mechanical parameters. The primary substitute identified is the IRF840ALPBF, which maintains identical electrical specifications across all critical parameters: N-Channel topology, 500V Vdss rating, 8A continuous drain current, 850mOhm Rds(on), gate threshold voltage, gate charge, and operating temperature range. Both devices utilize the same through-hole I2PAK package configuration (TO-262-3 Long Leads).

The substitution relationship is based on the following key parameters:

FET Type: N-Channel (identical)
Drain to Source Voltage (Vdss): 500V (identical)
Continuous Drain Current (Id): 8A (identical)
On-State Resistance (Rds On): 850mOhm @ 4.8A, 10V (identical)
Gate Threshold Voltage: 4V @ 250µA (identical)
Gate Charge: 38nC @ 10V (identical)
Operating Temperature Range: -55°C to 150°C (identical)
Package Type: Through Hole I2PAK (identical)

The IRF840ALPBF differs from the IRF840AL only in product status (Active versus Obsolete) and packaging format (Tube versus unspecified), with no electrical parameter deviation.

Parameter Comparison

Parameter	IRF840AL	IRF840ALPBF	Match
Manufacturer	Vishay Siliconix	Vishay Siliconix	Yes
FET Type	N-Channel	N-Channel	Yes
Technology	MOSFET (Metal Oxide)	MOSFET (Metal Oxide)	Yes
Drain to Source Voltage (Vdss)	500V	500V	Yes
Continuous Drain Current (Id) @ 25°C	8A (Tc)	8A (Tc)	Yes
Drive Voltage (Max Rds On)	10V	10V	Yes
Rds On (Max) @ Id, Vgs	850mOhm @ 4.8A, 10V	850mOhm @ 4.8A, 10V	Yes
Vgs(th) (Max) @ Id	4V @ 250µA	4V @ 250µA	Yes
Gate Charge (Qg) (Max) @ Vgs	38nC @ 10V	38nC @ 10V	Yes
Vgs (Max)	±30V	±30V	Yes
Input Capacitance (Ciss) (Max) @ Vds	1018pF @ 25V	1018pF @ 25V	Yes
Power Dissipation (Max)	3.1W (Ta), 125W (Tc)	3.1W (Ta), 125W (Tc)	Yes
Operating Temperature Range	-55°C to 150°C (TJ)	-55°C to 150°C (TJ)	Yes
Mounting Type	Through Hole	Through Hole	Yes
Package / Case	TO-262-3 Long Leads, I2PAK, TO-262AA	TO-262-3 Long Leads, I2PAK, TO-262AA	Yes
Product Status	Obsolete	Active	Different
RoHS Status	RoHS non-compliant	ROHS3 Compliant	Different

Engineering Selection Recommendations

The IRF840ALPBF is the direct functional equivalent of the IRF840AL. Selection between these parts is determined by application requirements and regulatory compliance mandates.

IRF840AL is suitable for applications where RoHS non-compliance is acceptable and where existing inventory or legacy design specifications require the original part designation. This device carries obsolete product status, indicating limited future availability.

IRF840ALPBF is the recommended selection for new designs and production continuity. This part maintains identical electrical and mechanical specifications while offering Active product status and ROHS3 compliance. The ROHS3 compliance status satisfies regulatory requirements in jurisdictions where RoHS compliance is mandatory. The Tube packaging format of the IRF840ALPBF supports automated assembly processes.

Both devices are manufactured by Vishay Siliconix and share the same base product number (IRF840), ensuring design compatibility at the circuit level. Pin configuration, footprint, and thermal characteristics are identical between the two parts.

Frequently Asked Questions (FAQ)

Q: Can the IRF840ALPBF be used as a direct replacement for the IRF840AL in existing designs?

A: Yes. The IRF840ALPBF is electrically and mechanically identical to the IRF840AL. All electrical parameters, including Vdss, Id, Rds(on), gate charge, and operating temperature range, are identical. Both devices use the same through-hole I2PAK package. No circuit modifications are required for substitution.

Q: What is the difference between the IRF840AL and IRF840ALPBF?

A: The primary differences are product status and RoHS compliance. The IRF840AL is obsolete and RoHS non-compliant. The IRF840ALPBF is an active product with ROHS3 compliance. Packaging format differs (unspecified for IRF840AL versus Tube for IRF840ALPBF), but this does not affect electrical performance or circuit compatibility.

Q: Why should I select the IRF840ALPBF over the IRF840AL?

A: The IRF840ALPBF offers active product status, ensuring continued availability and supply chain reliability. ROHS3 compliance satisfies regulatory requirements in regions where RoHS compliance is mandatory. For new designs and production applications, the IRF840ALPBF provides superior long-term support and compliance assurance.

Q: Are there any thermal or electrical performance differences between these parts?

A: No. Both devices have identical power dissipation ratings (3.1W at Ta, 125W at Tc), identical operating temperature ranges (-55°C to 150°C), and identical on-state resistance characteristics. Thermal performance in circuit applications is equivalent.

Q: What is the I2PAK package, and is it the same for both parts?

A: The I2PAK is a through-hole package designation (TO-262-3 Long Leads, TO-262AA). Both the IRF840AL and IRF840ALPBF use this identical package configuration. Pin spacing, lead length, and mounting hole positions are the same, ensuring direct PCB compatibility.

Q: Can I mix IRF840AL and IRF840ALPBF devices in the same production batch?

A: Yes. Since both devices are electrically and mechanically identical, they can be used interchangeably in the same circuit and on the same PCB. However, for consistency and traceability, it is standard practice to standardize on a single part number per design revision.

Q: What does ROHS3 compliance mean for the IRF840ALPBF?

A: ROHS3 compliance indicates that the IRF840ALPBF meets the Restriction of Hazardous Substances Directive 3 requirements, restricting the use of specific hazardous materials in electrical and electronic equipment. This compliance is required for sale in the European Union and many other jurisdictions.

Q: Is the IRF840AL still available for purchase?

A: The IRF840AL carries an obsolete product status, indicating that it is no longer in active production. While some inventory may remain available through distributors, future availability is not guaranteed. The IRF840ALPBF is the recommended alternative for ongoing supply assurance.

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