IRF740LC Equivalent & Substitute Parts

Part Overview

The IRF740LC 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 housed in a TO-220AB through-hole package and is designed for high-voltage switching applications. The IRF740LC is classified as obsolete, which necessitates identification of equivalent and substitute parts for ongoing design support and procurement.

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	550	mOhm @ 6A, 10V
Power Dissipation (Max)	125	W (Tc)
Operating Temperature	-55 to 150	°C (TJ)
Mounting Type	Through Hole	—
Package / Case	TO-220-3	—

Substitute Part Grouping Explanation

Substitution of the IRF740LC is determined by the following critical parameters:

Electrical Compatibility Requirements:

Drain to Source Voltage (Vdss) must be equal to or greater than 400V
Continuous Drain Current (Id) must be equal to or greater than 10A at 25°C
Gate drive voltage compatibility at 10V
Operating temperature range must encompass -55°C to 150°C (TJ)

Mechanical Compatibility Requirements:

Mounting type: Through Hole
Package / Case: TO-220-3 or equivalent TO-220 variant

Compliance Considerations:

RoHS3 compliance status
REACH compliance status

The substitute parts listed below meet these electrical and mechanical criteria and are classified as active products with current manufacturing status.

Parameter Comparison

Parameter	IRF740LC	IRF740LCPBF	FQP11N40C	STP11NK40Z	STP11NK50Z	STP7NK40Z
Manufacturer	Vishay Siliconix	Vishay Siliconix	onsemi	STMicroelectronics	STMicroelectronics	STMicroelectronics
Product Status	Obsolete	Active	Active	Active	Active	Active
FET Type	N-Channel	N-Channel	N-Channel	N-Channel	N-Channel	N-Channel
Vdss (V)	400	400	400	400	500	400
Id @ 25°C (A)	10	10	10.5	9	10	5.4
Rds On (Max) @ 10V (mOhm)	550 @ 6A	550 @ 6A	530 @ 5.25A	550 @ 4.5A	520 @ 4.5A	1000 @ 2.7A
Power Dissipation (Max) (W)	125	125	135	110	125	70
Operating Temperature (°C)	-55 to 150	-55 to 150	-55 to 150	-55 to 150	-55 to 150	-55 to 150
Package / Case	TO-220-3	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	ROHS3 Compliant
REACH Status	Unaffected	Unaffected	Unaffected	Unaffected	Unaffected	Unaffected

Engineering Selection Recommendations

Direct Equivalent (Identical Electrical and Mechanical Specifications):

IRF740LCPBF is the direct equivalent to IRF740LC. Both parts are manufactured by Vishay Siliconix and share identical electrical specifications: 400V Vdss, 10A continuous drain current, 550mOhm Rds On, and 125W power dissipation. The IRF740LCPBF is classified as active and is RoHS3 compliant, making it the preferred replacement for obsolete IRF740LC applications.

Primary Substitutes (Equivalent or Enhanced Performance):

FQP11N40C (onsemi) provides enhanced performance with 10.5A continuous drain current and 135W power dissipation while maintaining 400V Vdss and 530mOhm Rds On. This part is active and RoHS3 compliant.

STP11NK50Z (STMicroelectronics) offers increased voltage rating at 500V Vdss with 10A continuous drain current and 125W power dissipation. This part is active and RoHS3 compliant. The elevated voltage rating provides additional design margin for high-voltage applications.

STP11NK40Z (STMicroelectronics) maintains 400V Vdss with 9A continuous drain current and 110W power dissipation. This part is active and RoHS3 compliant. The reduced current rating and power dissipation make this suitable for lower-power applications.

Limited Substitution (Reduced Performance):

STP7NK40Z (STMicroelectronics) is rated for 400V Vdss but with only 5.4A continuous drain current and 70W power dissipation. This part is active and RoHS3 compliant. This device is suitable only for applications with reduced current requirements.

All substitute parts maintain the TO-220-3 through-hole package format and -55°C to 150°C operating temperature range, ensuring mechanical and thermal compatibility with IRF740LC designs.

Frequently Asked Questions (FAQ)

Q: Can IRF740LCPBF be used as a direct replacement for IRF740LC?

A: Yes. IRF740LCPBF is manufactured by the same supplier (Vishay Siliconix) and shares identical electrical specifications with IRF740LC: 400V Vdss, 10A continuous drain current, 550mOhm Rds On, and 125W power dissipation. The primary difference is product status (active versus obsolete) and RoHS3 compliance. Both devices use the TO-220-3 package.

Q: What is the difference between IRF740LC and FQP11N40C?

A: FQP11N40C is manufactured by onsemi and provides enhanced specifications: 10.5A continuous drain current (versus 10A) and 135W power dissipation (versus 125W). Both maintain 400V Vdss and similar Rds On characteristics. FQP11N40C is active and RoHS3 compliant. The increased current and power ratings make it suitable for higher-power applications.

Q: Why would STP11NK50Z be selected over other substitutes?

A: STP11NK50Z is selected when the application requires higher voltage margin. It is rated for 500V Vdss compared to 400V for IRF740LC, while maintaining 10A continuous drain current and 125W power dissipation. This higher voltage rating provides additional design headroom in high-voltage switching circuits. The part is active and RoHS3 compliant.

Q: Is STP7NK40Z a suitable substitute for all IRF740LC applications?

A: No. STP7NK40Z has reduced electrical performance with only 5.4A continuous drain current and 70W power dissipation compared to IRF740LC specifications of 10A and 125W. This part is suitable only for applications with lower current requirements. The 400V Vdss rating matches the original part.

Q: Are all substitute parts available in the same package as IRF740LC?

A: Yes. All substitute parts listed are housed in TO-220-3 through-hole packages, which are mechanically compatible with IRF740LC designs. No PCB layout modifications are required for package substitution.

Q: What is the compliance status of substitute parts?

A: All substitute parts are RoHS3 compliant and REACH unaffected. IRF740LC is RoHS non-compliant. For applications requiring RoHS compliance, IRF740LCPBF, FQP11N40C, STP11NK40Z, STP11NK50Z, and STP7NK40Z are all acceptable alternatives.

Q: Can substitute parts be used interchangeably in existing designs?

A: Substitution depends on application-specific requirements. IRF740LCPBF is a direct equivalent requiring no design changes. FQP11N40C, STP11NK40Z, and STP11NK50Z provide equivalent or enhanced performance and are suitable for most applications. STP7NK40Z has reduced current and power ratings and is suitable only for lower-power designs. Gate drive voltage (10V) and operating temperature range (-55°C to 150°C) are compatible across all parts.

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