IRF840LCSTRL Equivalent & Substitute Parts

Part Overview

The IRF840LCSTRL is an N-Channel MOSFET manufactured by Vishay Siliconix, rated for 500V drain-to-source voltage with 8A continuous drain current. This device is housed in a Surface Mount TO-263 (D2PAK) package and is classified as Active product status. The IRF840LCSTRL is used in high-voltage switching applications requiring reliable performance across industrial and consumer electronics domains. Substitute parts are identified to address inventory availability, enhanced performance characteristics, or compliance requirements while maintaining electrical and mechanical compatibility within the specified parameter ranges.

Substiute Parts

IRF840LCSTRL

Vishay SiliconixIn Stock: 2819IRF840LCSTRL Datasheet

Current PartRFQ

FDB12N50TM

onsemiIn Stock: 18284FDB12N50TM Datasheet

MFR RecommendedRFQ

STB11NK50ZT4

STMicroelectronicsIn Stock: 4404STB11NK50ZT4 Datasheet

MFR RecommendedRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitute parts for the IRF840LCSTRL are qualified based on the following electrical and mechanical compatibility criteria:

Primary Substitution Criteria:

• Drain to Source Voltage (Vdss): Equal to or greater than 500V
• FET Type: N-Channel
• Technology: MOSFET (Metal Oxide)
• Mounting Type: Surface Mount
• Package / Case: TO-263 (D2PAK) or equivalent mechanical footprint
• Operating Temperature Range: Minimum -55°C to 150°C (TJ)
• Gate Voltage (Vgs Max): ±30V or greater

Secondary Performance Considerations:

• Continuous Drain Current (Id): Equal to or greater than 8A
• Rds On (Max): Lower or equal values indicate improved performance
• Gate Charge (Qg): Lower values indicate faster switching characteristics
• Input Capacitance (Ciss): Values within reasonable range for application compatibility

The identified substitute parts meet or exceed these criteria while maintaining functional equivalence in high-voltage switching applications.

Parameter Comparison

Engineering Selection Recommendations

FDB12N50TM (onsemi)

The FDB12N50TM is a direct substitute offering superior electrical performance characteristics. This device provides 11.5A continuous drain current compared to the IRF840LCSTRL's 8A rating, with reduced on-resistance of 650mOhm versus 850mOhm. The FDB12N50TM achieves lower gate charge (30nC versus 39nC), enabling faster switching operation. This part is ROHS3 compliant and REACH unaffected, addressing regulatory requirements where the IRF840LCSTRL does not. The FDB12N50TM maintains identical voltage ratings (500V Vdss, ±30V Vgs) and operating temperature range (-55°C to 150°C). Inventory availability is substantial at 18,216 pieces.

STB11NK50ZT4 (STMicroelectronics)

The STB11NK50ZT4 provides an alternative with 10A continuous drain current and the lowest on-resistance of the substitute group at 520mOhm. This device delivers improved thermal performance with 125W maximum power dissipation at Tc, matching the IRF840LCSTRL specification. The STB11NK50ZT4 exhibits higher gate charge (68nC) compared to alternatives, which may impact switching speed in high-frequency applications. This part is ROHS3 compliant and REACH unaffected. Operating temperature range and voltage ratings are identical to the main part. Inventory availability is 4,361 pieces.

Compliance Considerations

Both substitute parts achieve ROHS3 compliance and REACH unaffected status, whereas the IRF840LCSTRL is RoHS non-compliant. Selection should account for regulatory requirements in target applications and end-use markets.

Frequently Asked Questions (FAQ)

Q: Can the FDB12N50TM directly replace the IRF840LCSTRL in existing designs?

A: Yes. The FDB12N50TM maintains identical voltage ratings (500V Vdss), gate voltage limits (±30V Vgs), and operating temperature range (-55°C to 150°C). Both devices use the TO-263 (D2PAK) package with identical pinout. The FDB12N50TM's higher current rating (11.5A versus 8A) and lower on-resistance (650mOhm versus 850mOhm) provide enhanced performance margins without requiring circuit modifications.

Q: What are the key differences between FDB12N50TM and STB11NK50ZT4?

A: Both devices share 500V Vdss rating and TO-263 packaging. The FDB12N50TM offers higher current capacity (11.5A versus 10A) and lower gate charge (30nC versus 68nC), enabling faster switching. The STB11NK50ZT4 provides the lowest on-resistance (520mOhm versus 650mOhm), resulting in reduced conduction losses. Gate charge differences affect switching speed; lower values reduce switching losses in high-frequency applications.

Q: Are there package compatibility concerns when substituting these parts?

A: No. All three devices use the TO-263-3 (D2PAK) package with identical mechanical footprint and pinout configuration. Surface mount assembly processes require no modification. Thermal interface requirements remain consistent across all three parts.

Q: How do the on-resistance specifications affect circuit performance?

A: On-resistance (Rds On) directly impacts conduction losses and heat generation. The STB11NK50ZT4 exhibits the lowest Rds On at 520mOhm, followed by FDB12N50TM at 650mOhm, and IRF840LCSTRL at 850mOhm. Lower on-resistance reduces power dissipation and improves efficiency, particularly in high-current applications. Selection depends on thermal management requirements and efficiency targets.

Q: What is the significance of gate charge differences?

A: Gate charge (Qg) determines the energy required to switch the device and influences switching speed. The FDB12N50TM has the lowest gate charge at 30nC, enabling faster switching transitions. The STB11NK50ZT4 has higher gate charge at 68nC. In high-frequency switching applications, lower gate charge reduces switching losses and improves overall system efficiency.

Q: Do the substitute parts meet the same regulatory requirements as the IRF840LCSTRL?

A: The IRF840LCSTRL is RoHS non-compliant. Both substitute parts (FDB12N50TM and STB11NK50ZT4) are ROHS3 compliant and REACH unaffected. Applications requiring RoHS compliance must use FDB12N50TM or STB11NK50ZT4. Both substitutes maintain identical ECCN (EAR99) and HTSUS (8541.29.0095) classifications.

Q: Are there thermal performance differences between these devices?

A: The FDB12N50TM provides the highest power dissipation rating at 165W (Tc), compared to 125W (Tc) for both IRF840LCSTRL and STB11NK50ZT4. This enhanced thermal capability allows the FDB12N50TM to operate at higher power levels or with reduced cooling requirements. The lower on-resistance of STB11NK50ZT4 (520mOhm) also reduces conduction losses compared to the main part.

Q: What moisture sensitivity level applies to all three devices?

A: All three devices have Moisture Sensitivity Level (MSL) of 1 (Unlimited), indicating no moisture sensitivity restrictions. Standard handling and storage procedures apply without special moisture control requirements.