IRF840L N-Channel 500V 8A MOSFET Equivalent & Substitute Parts

Part Overview

The IRF840L is an N-Channel MOSFET manufactured by Vishay Siliconix, rated for 500V drain-to-source voltage with 8A continuous drain current at 25°C. The device is packaged in a Through Hole I2PAK (TO-262-3) configuration and is rated for 125W power dissipation. The IRF840L is classified as obsolete, necessitating identification of equivalent and substitute components for new designs and ongoing production requirements. Substitute parts must maintain electrical compatibility across voltage, current, and thermal specifications while accommodating packaging and compliance requirements.

Substiute Parts

IRF840L

Vishay SiliconixIn Stock: 2515IRF840L Datasheet

Current PartRFQ

IRF840LCLPBF

Vishay SiliconixIn Stock: 1874IRF840LCLPBF Datasheet

DirectRFQ

STP8NM50N

STMicroelectronicsIn Stock: 2040STP8NM50N Datasheet

MFR RecommendedRFQ

STP9NK50Z

STMicroelectronicsIn Stock: 15967STP9NK50Z Datasheet

MFR RecommendedRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitution of the IRF840L is determined by strict adherence to the following electrical and mechanical parameters:

Primary Substitution Criteria:

• Drain to Source Voltage (Vdss): 500V minimum
• Continuous Drain Current (Id): 8A or greater at 25°C
• Drive Voltage: 10V gate drive compatibility
• Rds On (Max): 850mOhm or lower at specified Id and Vgs
• Power Dissipation: 125W or greater
• Operating Temperature Range: -55°C to 150°C minimum
• Mounting Type: Through Hole
• Technology: N-Channel MOSFET (Metal Oxide)

Secondary Compatibility Factors:

• Package compatibility (I2PAK or TO-220 footprints acceptable with PCB layout modification)
• RoHS compliance status
• Gate Charge characteristics
• Input Capacitance specifications

Substitute parts are grouped into two categories: direct equivalents maintaining identical packaging and performance characteristics, and functional substitutes with equivalent electrical performance in alternative packages.

Parameter Comparison

Engineering Selection Recommendations

IRF840LCLPBF (Direct Equivalent)

The IRF840LCLPBF is the primary substitute for the obsolete IRF840L. This part is manufactured by Vishay Siliconix and maintains identical electrical specifications including 500V Vdss, 8A continuous drain current, and 125W power dissipation. The IRF840LCLPBF is packaged in the same I2PAK (TO-262-3) configuration, enabling direct PCB footprint compatibility. The device is classified as Active product status and is ROHS3 compliant, addressing regulatory requirements for new production. Gate charge is reduced to 39nC compared to the original 63nC, and input capacitance is reduced to 1100pF, providing improved switching performance. Maximum gate voltage is increased to ±30V. This part is the recommended direct replacement for existing IRF840L designs.

STP9NK50Z (Functional Substitute - TO-220 Package)

The STP9NK50Z is manufactured by STMicroelectronics and operates within the 500V Vdss class with 7.2A continuous drain current, meeting the 8A requirement within acceptable tolerance. Power dissipation is rated at 110W, slightly below the original 125W specification. The device is packaged in TO-220-3 configuration, requiring PCB layout modification from the original I2PAK footprint. Gate charge is 32nC and input capacitance is 910pF, both lower than the original part, enabling faster switching characteristics. The STP9NK50Z is Active product status and ROHS3 compliant. This substitute is suitable for applications where package footprint modification is acceptable and current requirements do not exceed 7.2A.

STP8NM50N (Functional Substitute - TO-220 Package, Lower Current Rating)

The STP8NM50N is manufactured by STMicroelectronics and is rated for 500V Vdss with 5A continuous drain current. This part does not meet the 8A current requirement of the original IRF840L and is suitable only for applications with reduced current demands. Power dissipation is 45W, significantly lower than the original 125W specification. The device is packaged in TO-220-3 configuration. Gate charge is 14nC and input capacitance is 364pF, providing the lowest switching losses among the substitute options. The STP8NM50N is Active product status and ROHS3 compliant. This substitute is applicable only when circuit current requirements are confirmed below 5A.

Frequently Asked Questions (FAQ)

Q: Can the IRF840LCLPBF be used as a direct replacement for the IRF840L without PCB modifications?

A: Yes. The IRF840LCLPBF maintains identical I2PAK (TO-262-3) packaging and electrical specifications, enabling direct PCB footprint compatibility without layout modifications.

Q: What are the key differences between the IRF840LCLPBF and the original IRF840L?

A: The IRF840LCLPBF is Active product status versus Obsolete for the original part. Gate charge is reduced from 63nC to 39nC, and input capacitance is reduced from 1300pF to 1100pF. Maximum gate voltage is increased from ±20V to ±30V. RoHS compliance status is upgraded to ROHS3 Compliant.

Q: Can the STP9NK50Z or STP8NM50N be used as direct replacements without PCB modifications?

A: No. Both STMicroelectronics parts are packaged in TO-220-3 configuration, whereas the original IRF840L uses I2PAK (TO-262-3) packaging. PCB layout modification is required to accommodate the different footprint.

Q: What is the current rating difference between the IRF840L and the STP9NK50Z?

A: The IRF840L is rated for 8A continuous drain current at 25°C, while the STP9NK50Z is rated for 7.2A. The STP9NK50Z operates within acceptable tolerance for most applications but should be verified against specific circuit current requirements.

Q: Is the STP8NM50N suitable as a substitute for the IRF840L?

A: The STP8NM50N is rated for only 5A continuous drain current, which does not meet the 8A specification of the IRF840L. This part is suitable only for applications with confirmed current requirements below 5A.

Q: What are the compliance and regulatory differences between these parts?

A: The original IRF840L is RoHS non-compliant. All substitute parts (IRF840LCLPBF, STP9NK50Z, STP8NM50N) are ROHS3 compliant, meeting current regulatory requirements for new production and procurement.

Q: How do gate charge specifications affect switching performance?

A: Lower gate charge enables faster switching transitions. The IRF840LCLPBF reduces gate charge from 63nC to 39nC, the STP9NK50Z to 32nC, and the STP8NM50N to 14nC. Lower gate charge reduces driver power dissipation and improves switching speed, but requires verification of gate driver capability.

Q: What is the significance of input capacitance differences?

A: Input capacitance affects gate drive requirements and switching speed. The original IRF840L has 1300pF input capacitance. Substitute parts have lower values (IRF840LCLPBF: 1100pF, STP9NK50Z: 910pF, STP8NM50N: 364pF), reducing gate drive current requirements and enabling faster switching transitions.

Q: Are all substitute parts rated for the same operating temperature range?

A: Yes. All parts including the original IRF840L are rated for -55°C to 150°C junction temperature operating range.

Q: What power dissipation considerations apply when selecting a substitute?

A: The original IRF840L is rated for 125W power dissipation. The IRF840LCLPBF maintains this rating. The STP9NK50Z is rated for 110W, and the STP8NM50N for 45W. Thermal design must account for these differences, particularly in high-power applications.