IRF730 N-Channel MOSFET 400V 5.5A Equivalent & Substitute Parts

Part Overview

The IRF730 is an N-Channel MOSFET rated for 400V drain-to-source voltage with 5.5A continuous drain current in a Through Hole TO-220AB package. This device is classified as obsolete, which necessitates identification of equivalent and substitute components for ongoing design support and procurement. Active alternatives with compatible electrical and mechanical specifications are available from both the original manufacturer and qualified secondary sources.

Substiute Parts

IRF730

Vishay SiliconixIn Stock: 2663IRF730 Datasheet

Current PartRFQ

IRF730PBF

Vishay SiliconixIn Stock: 55199IRF730PBF Datasheet

DirectRFQ

STP11NK40Z

STMicroelectronicsIn Stock: 20302STP11NK40Z Datasheet

MFR RecommendedRFQ

STP7NK40Z

STMicroelectronicsIn Stock: 8094STP7NK40Z Datasheet

MFR RecommendedRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitution of the IRF730 is determined by strict equivalence across the following critical parameters:

Primary Equivalence Criteria:

• FET Type: N-Channel
• Technology: MOSFET (Metal Oxide)
• Drain to Source Voltage (Vdss): 400V minimum
• Continuous Drain Current (Id): 5.4A or greater
• Package / Case: TO-220-3
• Mounting Type: Through Hole

Secondary Compatibility Factors:

• Operating Temperature Range: -55°C to 150°C (TJ)
• Gate Drive Voltage: 10V
• Rds On characteristics at specified gate and drain conditions
• Gate Charge and Input Capacitance within acceptable ranges

Substitute parts are grouped into two categories:

Direct Equivalent (Identical Specifications): IRF730PBF maintains all electrical and mechanical parameters of the IRF730 with identical packaging and performance characteristics. The primary distinction is product status (Active vs. Obsolete) and RoHS compliance.

Functional Equivalents (Enhanced Performance): STP11NK40Z and STP7NK40Z are STMicroelectronics SuperMESH™ series devices that meet or exceed the IRF730 specifications. These parts maintain the 400V Vdss rating and TO-220-3 package while offering improved electrical characteristics such as lower Rds On values and reduced gate charge.

Parameter Comparison

Engineering Selection Recommendations

IRF730PBF is the direct equivalent replacement for the IRF730. This part is manufactured by Vishay Siliconix and maintains identical electrical specifications and TO-220AB packaging. The IRF730PBF is classified as Active with ROHS3 compliance, making it suitable for new designs and production continuity. Selection of IRF730PBF is appropriate when exact parameter matching and manufacturer continuity are required.

STP7NK40Z is a functional equivalent from STMicroelectronics that meets all critical substitution criteria. This device maintains the 400V Vdss rating and 5.4A continuous drain current, which is within 2% of the IRF730 specification. The STP7NK40Z offers reduced gate charge (26 nC vs. 38 nC) and lower input capacitance (535 pF vs. 700 pF), resulting in improved switching performance. This part is ROHS3 compliant and Active status. Selection of STP7NK40Z is appropriate for applications where improved switching characteristics and regulatory compliance are priorities.

STP11NK40Z is a higher-performance functional equivalent from STMicroelectronics with enhanced current rating (9A vs. 5.5A) and power dissipation (110W vs. 74W). While this device exceeds the IRF730 specifications, it maintains the 400V Vdss rating and TO-220-3 package. The STP11NK40Z features lower Rds On (0.55 Ohm vs. 1 Ohm) and reduced gate charge (32 nC vs. 38 nC). This part is ROHS3 compliant and Active status. Selection of STP11NK40Z is appropriate for applications requiring higher current capacity or improved thermal performance within the same package footprint.

All three substitute parts are compatible with the IRF730 in terms of pinout, thermal interface, and mounting requirements. Selection between alternatives depends on specific application requirements regarding current capacity, switching speed, and regulatory compliance.

Frequently Asked Questions (FAQ)

Q: Can IRF730PBF be used as a direct replacement for IRF730?

A: Yes. IRF730PBF is manufactured by Vishay Siliconix and maintains identical electrical specifications, gate drive requirements, and TO-220-3 package configuration. The primary differences are product status (Active vs. Obsolete) and RoHS compliance. No circuit modifications are required.

Q: What are the key differences between IRF730 and STP7NK40Z?

A: Both devices share the same 400V Vdss rating, TO-220-3 package, and comparable continuous drain current (5.5A vs. 5.4A). STP7NK40Z offers lower gate charge (26 nC vs. 38 nC), reduced input capacitance (535 pF vs. 700 pF), and improved Rds On characteristics. These improvements result in faster switching and reduced drive circuit losses. STP7NK40Z is manufactured by STMicroelectronics and is ROHS3 compliant.

Q: When should STP11NK40Z be selected over STP7NK40Z?

A: STP11NK40Z is selected when the application requires higher continuous drain current (9A vs. 5.4A) or greater power dissipation capability (110W vs. 70W). Both devices maintain the 400V Vdss rating and TO-220-3 package. STP11NK40Z is appropriate for higher-power applications or designs requiring thermal margin within the same package footprint.

Q: Are all substitute parts compatible with the IRF730 pinout?

A: Yes. IRF730PBF, STP11NK40Z, and STP7NK40Z all use the TO-220-3 package with identical pin configuration (Gate, Drain, Source). No PCB modifications are required for substitution.

Q: What is the impact of gate charge differences on circuit design?

A: Gate charge (Qg) determines the energy required to switch the MOSFET. IRF730 requires 38 nC, while STP7NK40Z requires 26 nC and STP11NK40Z requires 32 nC. Lower gate charge reduces drive circuit losses and enables faster switching. Existing gate drive circuits designed for IRF730 will operate with substitute parts, but improved performance is achieved with lower gate charge devices.

Q: Are there RoHS compliance considerations for substitute selection?

A: IRF730 is RoHS non-compliant. IRF730PBF, STP11NK40Z, and STP7NK40Z are all ROHS3 compliant. For applications subject to RoHS regulations or customer requirements, any of the three substitute parts satisfy compliance requirements.

Q: Can STP11NK40Z be used in applications designed for IRF730 without derating?

A: Yes. STP11NK40Z exceeds IRF730 specifications in current capacity and power dissipation while maintaining the same voltage rating and package. The device is electrically and mechanically compatible. Applications designed for IRF730 will operate within specification with STP11NK40Z, with potential for improved thermal performance.

Q: What is the operating temperature range for all substitute parts?

A: All substitute parts (IRF730PBF, STP11NK40Z, STP7NK40Z) maintain the same operating temperature range as IRF730: -55°C to 150°C (TJ). No thermal design modifications are required.