IRF740B N-Channel MOSFET 400V 10A TO-220-3 Equivalent & Substitute Parts

Part Overview

The IRF740B is an N-Channel Metal Oxide Semiconductor Field Effect Transistor (MOSFET) rated for 400V drain-to-source voltage with 10A continuous drain current at 25°C. This device is packaged in a Through Hole TO-220-3 configuration and is designed for high-voltage switching applications. The IRF740B carries an Obsolete product status, making identification of functionally equivalent active alternatives necessary for new designs and ongoing production requirements.

Key Parameters

Parameter	Value	Unit
FET Type	N-Channel	—
Drain to Source Voltage (Vdss)	400	V
Current - Continuous Drain (Id) @ 25°C	10	A (Tc)
Drive Voltage (Max Rds On)	10	V
Rds On (Max) @ Id, Vgs	540	mOhm @ 5A, 10V
Power Dissipation (Max)	134	W (Tc)
Operating Temperature Range	-55 to 150	°C (TJ)
Mounting Type	Through Hole	—
Package / Case	TO-220-3	—

Substitute Part Grouping Explanation

Substitution of the IRF740B is determined by the following critical parameters:

Primary Substitution Criteria:

Drain to Source Voltage (Vdss): 400V minimum
Continuous Drain Current (Id): 10A minimum at 25°C
Mounting Type: Through Hole
Package: TO-220-3 or compatible TO-220 variant
FET Type: N-Channel
Technology: MOSFET (Metal Oxide)
Operating Temperature Range: -55°C to 150°C

Secondary Compatibility Factors:

Gate Charge (Qg): Lower values indicate improved switching performance
On-State Resistance (Rds On): Lower values reduce conduction losses
Input Capacitance (Ciss): Lower values reduce gate drive requirements
Power Dissipation: Equal or higher ratings accommodate thermal requirements

Substitute parts are grouped into two categories based on voltage rating alignment:

Category 1: 400V Rated Devices — Direct voltage class equivalents offering comparable or improved electrical characteristics within the same voltage specification.

Category 2: 500V Rated Devices — Higher voltage rated alternatives suitable for applications where voltage margin is beneficial, with current and power ratings meeting or exceeding the IRF740B specification.

Parameter Comparison

Parameter	IRF740B	FQP11N40C	IRF740PBF	STP11NK40Z	IXFP12N50P	IXTP6N50D2
Manufacturer	onsemi	onsemi	Vishay Siliconix	STMicroelectronics	IXYS	IXYS
Vdss (V)	400	400	400	400	500	500
Id @ 25°C (A)	10	10.5	10	9	12	6
Rds On (Max) (mOhm)	540 @ 5A, 10V	530 @ 5.25A, 10V	550 @ 6A, 10V	550 @ 4.5A, 10V	500 @ 6A, 10V	500 @ 3A, 0V
Power Dissipation (W)	134	135	125	110	200	300
Gate Charge Qg (nC)	53 @ 10V	35 @ 10V	63 @ 10V	32 @ 10V	29 @ 10V	96 @ 5V
Input Capacitance Ciss (pF)	1800 @ 25V	1090 @ 25V	1400 @ 25V	930 @ 25V	1830 @ 25V	2800 @ 25V
Vgs(th) (Max) @ Id	4V @ 250µA	4V @ 250µA	4V @ 250µA	4.5V @ 100µA	5.5V @ 1mA	— (Depletion)
Vgs (Max)	±30V	±30V	±20V	±30V	±30V	±20V
Operating Temperature (°C)	-55 to 150	-55 to 150	-55 to 150	-55 to 150	-55 to 150	-55 to 150
Package	TO-220-3	TO-220-3	TO-220AB	TO-220	TO-220-3	TO-220-3
Product Status	Obsolete	Active	Active	Active	Active	Active
RoHS Status	Not Specified	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant

Engineering Selection Recommendations

Primary Recommendation: FQP11N40C (onsemi)

The FQP11N40C is the preferred direct substitute for the IRF740B. Both devices are manufactured by onsemi, share identical voltage and gate threshold specifications, and operate within the same temperature range. The FQP11N40C provides 10.5A continuous drain current, exceeding the IRF740B specification by 5 percent. On-state resistance is marginally lower at 530 mOhm versus 540 mOhm. Gate charge is reduced to 35 nC, improving switching efficiency. The device carries Active product status and ROHS3 compliance, supporting long-term design continuity. Packaging is specified as Tube with 20,460 units in stock.

Secondary Recommendation: IRF740PBF (Vishay Siliconix)

The IRF740PBF is a direct electrical equivalent manufactured by Vishay Siliconix. It maintains 400V Vdss and 10A continuous drain current specifications identical to the IRF740B. The device is packaged in TO-220AB, which is mechanically compatible with TO-220-3 footprints. Power dissipation is rated at 125W, slightly lower than the IRF740B at 134W. Gate charge is higher at 63 nC. The IRF740PBF carries Active product status and ROHS3 compliance. Maximum gate voltage is specified at ±20V, compared to ±30V for the IRF740B. This device is suitable for applications where Vishay component qualification is required.

Tertiary Recommendation: STP11NK40Z (STMicroelectronics)

The STP11NK40Z is a 400V rated N-Channel MOSFET with 9A continuous drain current, meeting the minimum voltage specification but providing slightly reduced current capacity. The device features the SuperMESH™ technology platform and delivers improved switching characteristics with gate charge of 32 nC and reduced input capacitance of 930 pF. Power dissipation is rated at 110W. The STP11NK40Z carries Active product status and ROHS3 compliance. This device is suitable for applications where current requirements are 9A or lower and switching efficiency is prioritized.

Higher Voltage Alternative: IXFP12N50P (IXYS)

The IXFP12N50P is a 500V rated N-Channel MOSFET with 12A continuous drain current, providing enhanced voltage margin and increased current capacity. This device is suitable for applications where higher voltage headroom is beneficial or where current requirements exceed 10A. Power dissipation is rated at 200W, providing substantial thermal margin. Gate charge is reduced to 29 nC, supporting efficient switching. The IXFP12N50P carries Active product status and ROHS3 compliance. Inventory availability is limited at 1,200 units.

Depletion Mode Alternative: IXTP6N50D2 (IXYS)

The IXTP6N50D2 is a 500V rated depletion-mode N-Channel MOSFET with 6A continuous drain current. This device operates with zero gate-source voltage in the on-state and is not a direct functional replacement for the enhancement-mode IRF740B. The IXTP6N50D2 is specified only for applications requiring depletion-mode operation and is not recommended as a general substitute.

Frequently Asked Questions (FAQ)

Q: Can the FQP11N40C directly replace the IRF740B without circuit modification?

A: Yes. The FQP11N40C is a direct substitute. Both devices share 400V Vdss, identical gate threshold voltage of 4V at 250µA, and ±30V maximum gate voltage. The FQP11N40C provides higher continuous drain current (10.5A versus 10A) and lower gate charge (35 nC versus 53 nC), making it functionally superior in the same circuit topology. No circuit modifications are required.

Q: What is the difference between TO-220-3 and TO-220AB packaging?

A: TO-220-3 and TO-220AB are mechanically compatible through-hole packages with identical pin configurations and footprints. Both accommodate three leads (Gate, Drain, Source) in the same physical arrangement. Devices specified as TO-220AB can be substituted into TO-220-3 footprints without modification.

Q: Why is the IXTP6N50D2 listed as a substitute if it has lower current rating?

A: The IXTP6N50D2 is a depletion-mode device, fundamentally different in operation from the enhancement-mode IRF740B. It is not a functional substitute for general applications. It is listed only because it was included in the provided substitute list and is suitable exclusively for circuits specifically designed for depletion-mode operation.

Q: Is the IRF740PBF suitable for new designs?

A: Yes. The IRF740PBF carries Active product status and ROHS3 compliance. It is electrically equivalent to the IRF740B with identical voltage and current ratings. The device is suitable for new designs where Vishay component qualification is required or preferred. Maximum gate voltage specification is ±20V, which should be verified against circuit requirements.

Q: What is the advantage of the STP11NK40Z over the FQP11N40C?

A: The STP11NK40Z features lower gate charge (32 nC versus 35 nC) and significantly lower input capacitance (930 pF versus 1,090 pF). These characteristics reduce gate drive power and improve switching speed. However, continuous drain current is reduced to 9A. The STP11NK40Z is preferred in applications where current requirements are 9A or lower and switching efficiency is critical.

Q: Can the 500V rated devices (IXFP12N50P, IXTP6N50D2) be used in 400V applications?

A: Yes. Devices rated for higher voltage can be used in lower voltage applications. The 500V rating provides additional voltage margin and does not degrade performance in 400V circuits. However, the IXTP6N50D2 is a depletion-mode device and is not a functional substitute for enhancement-mode applications.

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

A: Gate charge determines the energy required to switch the device on and off. Higher gate charge (IRF740PBF at 63 nC) requires more gate drive current and energy compared to lower gate charge devices (FQP11N40C at 35 nC, STP11NK40Z at 32 nC). In circuits with limited gate drive capability, lower gate charge devices reduce switching losses and improve efficiency.

Q: Are all substitute parts ROHS3 compliant?

A: All active substitute parts listed (FQP11N40C, IRF740PBF, STP11NK40Z, IXFP12N50P, IXTP6N50D2) carry ROHS3 compliance certification. The original IRF740B does not specify RoHS status. ROHS3 compliance ensures compliance with Restriction of Hazardous Substances regulations for new designs and production.

Request Quote (Ships tomorrow)

Part Number

Quantity

Company

Contact Name

E-mail

Message