IRF840STRRPBF Equivalent & Substitute Parts

Part Overview

The IRF840STRRPBF is an N-Channel MOSFET manufactured by Vishay Siliconix, rated for 500V drain-to-source voltage with 8A continuous drain current at 25°C. This device is housed in a Surface Mount TO-263 (D2PAK) package and is classified as Active product status. The IRF840STRRPBF is suitable for high-voltage switching applications requiring moderate current handling and thermal dissipation up to 125W.

Substitute parts become necessary when the primary device is unavailable, when inventory constraints exist, or when design requirements allow for alternative components with equivalent or superior electrical characteristics within the same package family.

Substiute Parts

IRF840STRRPBF

Vishay SiliconixIn Stock: 3545IRF840STRRPBF Datasheet

Current PartRFQ

FDB12N50FTM-WS

onsemiIn Stock: 746FDB12N50FTM-WS Datasheet

MFR RecommendedRFQ

STB11NK50ZT4

STMicroelectronicsIn Stock: 4404STB11NK50ZT4 Datasheet

MFR RecommendedRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitution of the IRF840STRRPBF is determined by the following critical electrical and mechanical parameters:

Mandatory Compatibility Criteria:

• Drain to Source Voltage (Vdss): Must equal or exceed 500V
• Package Type: Must be Surface Mount TO-263 (D2PAK) or equivalent footprint
• FET Type: Must be N-Channel MOSFET
• Operating Temperature Range: Must support -55°C to 150°C (TJ)
• RoHS Compliance: Must meet ROHS3 standard

Performance Parameters Allowing Substitution:

• Continuous Drain Current (Id): Substitute parts may equal or exceed 8A
• Rds On (Max): Lower values indicate improved performance
• Power Dissipation (Max): Equal or higher ratings are acceptable
• Gate Charge (Qg): Lower values reduce switching losses
• Input Capacitance (Ciss): Lower values reduce input drive requirements

The substitute parts listed below meet all mandatory criteria and provide equivalent or enhanced electrical performance within the same package family.

Parameter Comparison

Engineering Selection Recommendations

IRF840STRRPBF (Primary Component)

The IRF840STRRPBF maintains Active product status with full manufacturer support and availability. This device is the baseline reference for substitution analysis and should be selected when inventory is available and cost is not a primary constraint.

FDB12N50FTM-WS (onsemi Substitute)

The FDB12N50FTM-WS is manufactured by onsemi under the UniFET™ series and provides superior electrical performance with 11.5A continuous drain current and reduced Rds On of 700mOhm. Gate charge is significantly lower at 30nC, reducing switching losses. However, this device carries Obsolete product status, indicating limited long-term availability. Selection of this substitute should account for potential future supply constraints.

STB11NK50ZT4 (STMicroelectronics Substitute)

The STB11NK50ZT4 is manufactured by STMicroelectronics under the SuperMESH™ series and maintains Active product status. This device provides 10A continuous drain current with superior Rds On performance of 520mOhm, representing the lowest on-resistance among all listed options. The STB11NK50ZT4 is suitable for applications where reduced conduction losses and improved thermal efficiency are required. Inventory availability is higher at 4361 pieces compared to the main part at 3500 pieces.

All substitute parts comply with ROHS3 standards, support the full operating temperature range of -55°C to 150°C, and are housed in compatible TO-263 (D2PAK) Surface Mount packages.

Frequently Asked Questions (FAQ)

Q: Can the FDB12N50FTM-WS be used as a direct replacement for the IRF840STRRPBF?

A: The FDB12N50FTM-WS meets all mandatory compatibility criteria: identical 500V Vdss rating, N-Channel MOSFET technology, Surface Mount TO-263 (D2PAK) package, and full operating temperature range support. The higher 11.5A continuous drain current and lower Rds On provide equivalent or superior performance. However, Obsolete product status should be considered for long-term design viability.

Q: What are the key differences between the STB11NK50ZT4 and the IRF840STRRPBF?

A: Both devices share identical 500V Vdss rating, 125W power dissipation, and operating temperature range. The STB11NK50ZT4 provides higher continuous drain current (10A vs. 8A) and significantly lower Rds On (520mOhm vs. 850mOhm), resulting in reduced conduction losses. The STB11NK50ZT4 maintains Active product status with higher inventory availability.

Q: Are all substitute parts in the same package?

A: All listed substitute parts use Surface Mount TO-263 (D2PAK) packaging with identical pinout and footprint compatibility. Direct PCB layout substitution is possible without design modifications.

Q: Which substitute part offers the best thermal performance?

A: The FDB12N50FTM-WS provides the highest power dissipation rating at 165W (Tc), compared to 125W for both the main part and the STB11NK50ZT4. However, the STB11NK50ZT4 offers the lowest Rds On at 520mOhm, which reduces conduction losses and heat generation during operation.

Q: Do all parts meet environmental compliance standards?

A: All listed parts comply with ROHS3 standards and carry Moisture Sensitivity Level (MSL) rating of 1 (Unlimited). The STB11NK50ZT4 and FDB12N50FTM-WS both carry REACH Unaffected status.

Q: What is the significance of gate charge differences between these devices?

A: Gate charge (Qg) determines the energy required to switch the MOSFET on and off. The FDB12N50FTM-WS has significantly lower gate charge at 30nC compared to 63nC for the IRF840STRRPBF, reducing driver power requirements and enabling faster switching transitions in high-frequency applications.

Q: Can these parts be used interchangeably in existing designs?

A: Electrical interchangeability is confirmed for all listed substitute parts within the specified parameter ranges. PCB layout and thermal management design remain unchanged due to identical packaging. Circuit performance may improve due to lower Rds On values in substitute parts, reducing power dissipation and improving efficiency.