IRF740LCS Equivalent & Substitute Parts

Part Overview

The IRF740LCS is an N-Channel MOSFET manufactured by Vishay Siliconix, rated for 400V drain-to-source voltage with 10A continuous drain current at 25°C. The device is packaged in a surface mount TO-263 (D2PAK) configuration and operates across a temperature range of -55°C to 150°C. The IRF740LCS is classified as obsolete, necessitating identification of equivalent and substitute components for new designs and ongoing production requirements. Substitute parts listed maintain electrical compatibility within specified parameter tolerances while offering active product status and improved availability.

Substiute Parts

IRF740LCS

Vishay SiliconixIn Stock: 2863IRF740LCS Datasheet

Current PartRFQ

FQP11N40C

onsemiIn Stock: 20567FQP11N40C Datasheet

MFR RecommendedRFQ

STP11NK40Z

STMicroelectronicsIn Stock: 20302STP11NK40Z Datasheet

MFR RecommendedRFQ

STP7NK40Z

STMicroelectronicsIn Stock: 8094STP7NK40Z Datasheet

MFR RecommendedRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitution of the IRF740LCS is determined by electrical parameter compatibility across the following critical specifications:

Electrical Compatibility Criteria:

• Drain-to-Source Voltage (Vdss): 400V minimum
• Continuous Drain Current (Id): 10A or greater at 25°C
• Gate Threshold Voltage (Vgs(th)): 4V or less at specified gate current
• Maximum Gate-Source Voltage (Vgs): ±30V
• Operating Temperature Range: -55°C to 150°C minimum

Mechanical Compatibility Considerations:

• FET Type: N-Channel
• Technology: MOSFET (Metal Oxide)
• Package compatibility: Substitute parts listed are available in through-hole TO-220 packaging, which differs from the original surface mount D2PAK configuration. This represents a packaging change that requires PCB redesign.

All substitute parts maintain N-Channel MOSFET topology with 400V Vdss rating and equivalent or superior continuous drain current ratings. Substitute parts are classified as active products with current manufacturing status and improved long-term availability compared to the obsolete IRF740LCS.

Parameter Comparison

Engineering Selection Recommendations

FQP11N40C (onsemi): FQP11N40C is the primary substitute for IRF740LCS applications requiring maximum electrical compatibility. This device provides 10.5A continuous drain current, exceeding the original 10A specification, with equivalent 400V Vdss rating. Gate charge of 35 nC is lower than the IRF740LCS at 39 nC, resulting in improved switching performance. The device is ROHS3 compliant and maintains active product status with 20,460 units in stock. Power dissipation capability of 135W (Tc) supports thermal management in high-current applications. Packaging transition from surface mount D2PAK to through-hole TO-220-3 requires PCB redesign.

STP11NK40Z (STMicroelectronics): STP11NK40Z provides electrical compatibility with 9A continuous drain current, slightly below the original 10A specification. This device maintains 400V Vdss and equivalent 550 mOhm Rds On characteristics. Gate charge of 32 nC and input capacitance of 930 pF represent improvements over the IRF740LCS. The device is ROHS3 compliant with active product status and 20,200 units in stock. Power dissipation of 110W (Tc) is suitable for moderate-power applications. Vgs(th) of 4.5V is marginally higher than the original specification.

STP7NK40Z (STMicroelectronics): STP7NK40Z is suitable for applications where continuous drain current requirements are 5.4A or less. This device maintains 400V Vdss rating with reduced gate charge of 26 nC and input capacitance of 535 pF, enabling faster switching operation. Rds On of 1 Ohm at 2.7A represents higher on-resistance compared to the original specification. Power dissipation of 70W (Tc) limits application to lower-power circuits. The device is ROHS3 compliant with active product status and 8,042 units in stock. This substitute is appropriate only for current-limited applications.

All substitute parts maintain the required -55°C to 150°C operating temperature range and ±30V maximum gate-source voltage specification. Selection between FQP11N40C and STP11NK40Z depends on specific application current requirements and thermal management constraints. STP7NK40Z is limited to applications with reduced current demands.

Frequently Asked Questions (FAQ)

Q: Can FQP11N40C directly replace IRF740LCS without circuit modification?

A: FQP11N40C maintains electrical compatibility with IRF740LCS across all critical parameters including Vdss, gate threshold voltage, and operating temperature range. However, packaging differs: IRF740LCS uses surface mount TO-263 (D2PAK) while FQP11N40C uses through-hole TO-220-3. PCB redesign is required for mechanical mounting. No circuit modification is necessary for electrical operation.

Q: What is the primary difference between FQP11N40C and STP11NK40Z?

A: Both devices provide 400V Vdss and equivalent Rds On characteristics. FQP11N40C offers 10.5A continuous drain current versus 9A for STP11NK40Z. FQP11N40C provides 135W power dissipation compared to 110W for STP11NK40Z. Gate charge is 35 nC for FQP11N40C versus 32 nC for STP11NK40Z. Selection depends on application current and thermal requirements.

Q: Is STP7NK40Z suitable for all IRF740LCS applications?

A: STP7NK40Z is limited to applications where continuous drain current does not exceed 5.4A. The original IRF740LCS is rated for 10A continuous drain current. STP7NK40Z exhibits higher on-resistance of 1 Ohm at 2.7A compared to 550 mOhm for IRF740LCS at higher current levels. This substitute is appropriate only for reduced-current applications.

Q: What are the RoHS compliance implications of substitution?

A: IRF740LCS is RoHS non-compliant. All substitute parts (FQP11N40C, STP11NK40Z, STP7NK40Z) are ROHS3 compliant. Substitution with any listed part improves regulatory compliance for new designs and production.

Q: How do gate charge differences affect circuit performance?

A: IRF740LCS has gate charge of 39 nC at 10V. FQP11N40C provides 35 nC, STP11NK40Z provides 32 nC, and STP7NK40Z provides 26 nC. Lower gate charge reduces switching time and driver power requirements. Substitute parts with lower gate charge enable faster switching operation and reduced gate driver stress.

Q: Are all substitute parts available in the same packaging as IRF740LCS?

A: No. IRF740LCS uses surface mount TO-263 (D2PAK) packaging. All substitute parts use through-hole TO-220-3 packaging. This represents a significant mechanical change requiring PCB layout redesign for mounting and thermal management.

Q: What is the impact of Vgs(th) variation between parts?

A: IRF740LCS specifies Vgs(th) of 4V at 250µA. FQP11N40C maintains 4V at 250µA. STP11NK40Z and STP7NK40Z specify 4.5V at lower gate currents (100µA and 50µA respectively). Threshold voltage variation affects gate drive circuit design and switching characteristics. Higher threshold voltages require proportionally higher gate drive voltages for equivalent switching performance.

Q: Can substitute parts be used in high-temperature applications?

A: All substitute parts maintain the required -55°C to 150°C operating temperature range specified for IRF740LCS. Thermal management design must account for package differences: TO-220-3 through-hole packages have different thermal characteristics than surface mount D2PAK packages.