IRF740 N-Channel MOSFET 400V 10A Equivalent & Substitute Parts

Part Overview

The IRF740 is an N-Channel MOSFET rated for 400V drain-to-source voltage with 10A continuous drain current in a Through Hole TO-220AB package. This device is classified as Obsolete, necessitating identification of equivalent and substitute components for new designs and production continuity. Active alternatives with comparable electrical characteristics and identical package configurations are available from multiple manufacturers.

Key Parameters

Parameter	Value	Unit
Drain to Source Voltage (Vdss)	400	V
Continuous Drain Current (Id) @ 25°C	10	A (Tc)
On-State Resistance (Rds On Max) @ Id, Vgs	550 mOhm @ 6A, 10V	Ohm
Gate Threshold Voltage (Vgs(th) Max) @ Id	4	V @ 250µA
Gate Charge (Qg Max) @ Vgs	63	nC @ 10V
Power Dissipation (Max)	125	W (Tc)
Operating Temperature Range	-55 to 150	°C (TJ)
Package Type	TO-220-3	Through Hole

Substitute Part Grouping Explanation

Substitution of the IRF740 is determined by the following critical parameters:

Electrical Compatibility Requirements:

Drain to Source Voltage (Vdss): 400V minimum
Continuous Drain Current (Id): 10A or greater at 25°C
Gate Drive Voltage: 10V compatible
Operating Temperature Range: -55°C to 150°C minimum
Package Configuration: TO-220-3 Through Hole

Substitution Logic: Parts are classified as direct equivalents or functional substitutes based on matching or exceeding the IRF740 electrical ratings while maintaining identical package geometry. The IRF740PBF represents a direct equivalent with identical electrical specifications but improved product status (Active vs. Obsolete) and enhanced compliance. The FQP11N40C, STP11NK40Z, and STP7NK40Z are functional substitutes that meet or exceed the voltage and current requirements with variations in secondary parameters such as gate charge, input capacitance, and power dissipation.

Parameter Comparison

Parameter	IRF740	IRF740PBF	FQP11N40C	STP11NK40Z	STP7NK40Z
Manufacturer	Vishay Siliconix	Vishay Siliconix	onsemi	STMicroelectronics	STMicroelectronics
Product Status	Obsolete	Active	Active	Active	Active
Vdss (V)	400	400	400	400	400
Id @ 25°C (A)	10	10	10.5	9	5.4
Rds On Max @ Id, Vgs (mOhm)	550 @ 6A, 10V	550 @ 6A, 10V	530 @ 5.25A, 10V	550 @ 4.5A, 10V	1000 @ 2.7A, 10V
Vgs(th) Max @ Id (V)	4 @ 250µA	4 @ 250µA	4 @ 250µA	4.5 @ 100µA	4.5 @ 50µA
Gate Charge Qg Max @ 10V (nC)	63	63	35	32	26
Input Capacitance Ciss Max @ 25V (pF)	1400	1400	1090	930	535
Power Dissipation Max (W)	125	125	135	110	70
Operating Temperature (°C)	-55 to 150	-55 to 150	-55 to 150	-55 to 150	-55 to 150
Package	TO-220-3	TO-220-3	TO-220-3	TO-220-3	TO-220-3
RoHS Status	Non-compliant	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant

Engineering Selection Recommendations

Direct Equivalent (Recommended for Obsolete Part Replacement):

IRF740PBF is the primary replacement for IRF740. This part maintains identical electrical specifications (400V Vdss, 10A Id, 550mOhm Rds On, 63nC gate charge) while offering Active product status and ROHS3 compliance. The IRF740PBF is packaged in Tube format and represents a direct form-fit-function substitute with superior availability and regulatory compliance.

Functional Substitutes (For Design Flexibility):

FQP11N40C (onsemi) provides enhanced performance with 10.5A continuous drain current, 135W power dissipation, and reduced gate charge (35nC). This part is suitable for applications requiring improved thermal performance or faster switching characteristics.

STP11NK40Z (STMicroelectronics) offers 9A continuous drain current with reduced gate charge (32nC) and input capacitance (930pF), making it suitable for applications prioritizing switching speed and gate drive efficiency.

STP7NK40Z (STMicroelectronics) is rated for 5.4A continuous drain current with significantly reduced gate charge (26nC) and input capacitance (535pF). This part is appropriate for lower-current applications or designs requiring minimal gate drive power.

All substitute parts maintain the 400V Vdss rating, TO-220-3 package configuration, and -55°C to 150°C operating temperature range. Selection should be based on specific application current requirements and thermal management constraints.

Frequently Asked Questions (FAQ)

Q: Can IRF740PBF be used as a direct replacement for IRF740?

A: Yes. IRF740PBF is electrically and mechanically identical to IRF740, with matching Vdss (400V), Id (10A), Rds On (550mOhm), and gate charge (63nC) specifications. The primary differences are Active product status and ROHS3 compliance, making it the preferred replacement for obsolete IRF740 units.

Q: What is the difference between IRF740PBF and FQP11N40C?

A: Both parts meet the 400V/10A requirement. FQP11N40C provides higher continuous drain current (10.5A), greater power dissipation capability (135W vs. 125W), and lower gate charge (35nC vs. 63nC). The reduced gate charge enables faster switching and lower gate drive power consumption. FQP11N40C is manufactured by onsemi, while IRF740PBF is from Vishay Siliconix.

Q: Can STP7NK40Z replace IRF740 in all applications?

A: STP7NK40Z is suitable only for applications where the continuous drain current requirement does not exceed 5.4A. While it maintains the 400V Vdss rating and TO-220-3 package, its lower current rating (5.4A vs. 10A) and higher on-state resistance (1Ohm vs. 550mOhm) limit its use to lower-power designs. Verify application current requirements before selection.

Q: Are all substitute parts RoHS compliant?

A: IRF740PBF, FQP11N40C, STP11NK40Z, and STP7NK40Z are all ROHS3 compliant. The original IRF740 is RoHS non-compliant. For applications requiring RoHS compliance, any of the substitute parts are acceptable.

Q: What is the significance of gate charge differences among these parts?

A: Gate charge (Qg) determines the energy required to switch the MOSFET on and off. Lower gate charge (FQP11N40C: 35nC, STP11NK40Z: 32nC, STP7NK40Z: 26nC) reduces gate drive power consumption and enables faster switching compared to IRF740/IRF740PBF (63nC). Selection depends on gate driver capability and switching frequency requirements.

Q: Do all substitute parts use the same pinout?

A: Yes. All listed parts use the TO-220-3 package with identical pin configuration: Gate (pin 1), Drain (pin 2), Source (pin 3). No circuit board modifications are required for mechanical substitution.

Q: What is the impact of input capacitance differences?

A: Input capacitance (Ciss) affects gate charge and switching speed. Lower Ciss values (FQP11N40C: 1090pF, STP11NK40Z: 930pF, STP7NK40Z: 535pF) result in faster switching transitions and reduced gate drive requirements compared to IRF740/IRF740PBF (1400pF). Applications with high switching frequencies benefit from lower Ciss values.

Q: Are there inventory considerations for part selection?

A: IRF740PBF (20,100 pcs), FQP11N40C (20,460 pcs), and STP11NK40Z (20,200 pcs) have comparable high inventory levels. STP7NK40Z has lower inventory (8,042 pcs). For production continuity, IRF740PBF, FQP11N40C, or STP11NK40Z are preferred.

Request Quote (Ships tomorrow)

Part Number

Quantity

Company

Contact Name

E-mail

Message