IRF730SPBF Equivalent & Substitute Parts

Part Overview

The IRF730SPBF is an N-Channel MOSFET manufactured by Vishay Siliconix, rated for 400V drain-to-source voltage with 5.5A continuous drain current. This device is housed in a Surface Mount TO-263 (D2PAK) package and is designed for applications requiring moderate voltage and current switching capabilities. The part maintains Active product status and is RoHS3 compliant.

Substitute parts are identified when equivalent electrical performance can be achieved within the specified parameter ranges while maintaining the same package form factor and mounting technology. The IRF730SPBF operates across a wide temperature range of -55°C to 150°C (TJ) and dissipates up to 3.1W at ambient temperature or 74W at case temperature.

Key Parameters

Parameter	Value	Unit
Drain to Source Voltage (Vdss)	400	V
Continuous Drain Current (Id) @ 25°C	5.5	A (Tc)
Drive Voltage (Max Rds On)	10	V
Rds On (Max) @ Id, Vgs	1	Ohm @ 3.3A, 10V
Gate Threshold Voltage Vgs(th) (Max) @ Id	4	V @ 250µA
Gate Charge (Qg) (Max) @ Vgs	38	nC @ 10V
Maximum Gate Voltage (Vgs)	±20	V
Input Capacitance (Ciss) (Max) @ Vds	700	pF @ 25V
Power Dissipation (Max)	3.1 (Ta), 74 (Tc)	W
Operating Temperature Range	-55 to 150	°C (TJ)
Mounting Type	Surface Mount	—
Package / Case	TO-263-3, D2PAK	—
FET Type	N-Channel	—
Technology	MOSFET (Metal Oxide)	—

Substitute Part Grouping Explanation

Substitution of the IRF730SPBF is determined by strict equivalence across the following critical parameters:

Voltage Rating Equivalence: The substitute part must maintain a Drain to Source Voltage (Vdss) rating of 400V or greater to ensure safe operation in the same circuit topology.

Current Capability: The substitute part must support a continuous drain current (Id) rating equal to or exceeding 5.5A at 25°C case temperature to handle the same load conditions.

Package Compatibility: The substitute part must use the Surface Mount TO-263 (D2PAK) package to ensure mechanical and thermal compatibility with existing PCB layouts and thermal management designs.

Gate Drive Voltage: The substitute part must operate with a maximum Rds On specification at 10V gate drive voltage, ensuring compatibility with standard gate driver circuits.

Temperature Range: The substitute part must support the full operating temperature range of -55°C to 150°C (TJ) to maintain performance across all environmental conditions.

Compliance Status: The substitute part must maintain RoHS3 compliance and Moisture Sensitivity Level (MSL) of 1 (Unlimited) to meet regulatory and manufacturing requirements.

The STB11NK40ZT4 meets all substitution criteria and is classified as a manufacturer-recommended equivalent.

Parameter Comparison

Parameter	IRF730SPBF (Vishay Siliconix)	STB11NK40ZT4 (STMicroelectronics)	Compatibility
Drain to Source Voltage (Vdss)	400 V	400 V	Equivalent
Continuous Drain Current (Id) @ 25°C	5.5 A (Tc)	9 A (Tc)	Substitute Exceeds
Drive Voltage (Max Rds On)	10 V	10 V	Equivalent
Rds On (Max) @ Id, Vgs	1 Ohm @ 3.3A, 10V	550 mOhm @ 4.5A, 10V	Substitute Lower
Gate Threshold Voltage Vgs(th) (Max) @ Id	4 V @ 250µA	4.5 V @ 100µA	Similar
Gate Charge (Qg) (Max) @ Vgs	38 nC @ 10V	32 nC @ 10V	Substitute Lower
Maximum Gate Voltage (Vgs)	±20 V	±30 V	Substitute Exceeds
Input Capacitance (Ciss) (Max) @ Vds	700 pF @ 25V	930 pF @ 25V	Substitute Higher
Power Dissipation (Max)	3.1 W (Ta), 74 W (Tc)	110 W (Tc)	Substitute Exceeds
Operating Temperature Range	-55 to 150 °C (TJ)	-55 to 150 °C (TJ)	Equivalent
Mounting Type	Surface Mount	Surface Mount	Equivalent
Package / Case	TO-263-3, D2PAK	TO-263-3, D2PAK	Equivalent
FET Type	N-Channel	N-Channel	Equivalent
Technology	MOSFET (Metal Oxide)	MOSFET (Metal Oxide)	Equivalent
RoHS Status	ROHS3 Compliant	ROHS3 Compliant	Equivalent
Moisture Sensitivity Level (MSL)	1 (Unlimited)	1 (Unlimited)	Equivalent

Engineering Selection Recommendations

Primary Selection: The IRF730SPBF remains the primary component choice when original specifications are required and inventory is available. Both the main part and substitute maintain Active product status and full RoHS3 compliance.

Substitute Selection Criteria: The STB11NK40ZT4 is suitable as a direct substitute when the IRF730SPBF is unavailable. The substitute part exceeds the original specifications in continuous drain current (9A versus 5.5A), power dissipation capability (110W Tc versus 74W Tc), and maximum gate voltage rating (±30V versus ±20V). These enhancements provide additional design margin without compromising circuit compatibility.

Package and Mounting Compatibility: Both parts use identical Surface Mount TO-263 (D2PAK) packaging, ensuring mechanical fit and thermal interface compatibility with existing PCB designs.

Compliance and Certification: Both parts maintain RoHS3 compliance, MSL Level 1 (Unlimited), and identical ECCN and HTSUS classifications, satisfying regulatory and supply chain requirements.

Thermal Management: The STB11NK40ZT4 provides superior thermal performance with 110W maximum power dissipation at case temperature compared to 74W for the IRF730SPBF, allowing for more efficient thermal design in applications operating near maximum ratings.

Frequently Asked Questions (FAQ)

Q: Can the STB11NK40ZT4 be used as a direct replacement for the IRF730SPBF in existing designs?

A: Yes. Both parts share identical voltage ratings (400V Vdss), equivalent gate drive voltage requirements (10V), matching operating temperature ranges (-55°C to 150°C TJ), and identical Surface Mount TO-263 (D2PAK) packaging. The substitute part exceeds the original current and power dissipation specifications, providing enhanced performance margin.

Q: What are the key differences between these two parts?

A: The STB11NK40ZT4 provides higher continuous drain current (9A versus 5.5A), lower on-resistance (550mOhm versus 1 Ohm at specified conditions), lower gate charge (32nC versus 38nC), higher maximum gate voltage (±30V versus ±20V), and superior power dissipation capability (110W versus 74W at case temperature). Input capacitance is slightly higher (930pF versus 700pF).

Q: Are both parts RoHS3 compliant?

A: Yes. Both the IRF730SPBF and STB11NK40ZT4 are RoHS3 compliant with MSL Level 1 (Unlimited) moisture sensitivity ratings.

Q: Do these parts require different PCB layouts or thermal management approaches?

A: No. Both parts use identical TO-263 (D2PAK) Surface Mount packaging with the same pinout and thermal interface. Existing PCB layouts and thermal management designs are fully compatible with either part.

Q: What is the gate charge difference and does it affect circuit design?

A: The STB11NK40ZT4 has lower gate charge (32nC versus 38nC at 10V), which results in faster switching transitions and reduced gate driver power consumption. This is a beneficial characteristic that does not require circuit redesign.

Q: Can the substitute part handle higher current applications than the original?

A: Yes. The STB11NK40ZT4 is rated for 9A continuous drain current compared to 5.5A for the IRF730SPBF. Applications requiring higher current switching can utilize the substitute part's enhanced current capability within the same 400V voltage rating.

Q: Are the operating temperature ranges identical?

A: Yes. Both parts operate across the full temperature range of -55°C to 150°C (TJ), ensuring equivalent thermal performance across all environmental conditions.

Q: What is the significance of the lower on-resistance in the substitute part?

A: The STB11NK40ZT4 exhibits lower on-resistance (550mOhm versus 1 Ohm at specified conditions), resulting in reduced conduction losses and lower junction temperature during operation. This characteristic improves overall circuit efficiency and thermal performance.

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