IRF840ASTRL MOSFET N-Channel 500V 8A Equivalent & Substitute Parts

Part Overview

The IRF840ASTRL is an N-Channel MOSFET manufactured by Vishay Siliconix, rated for 500V drain-to-source voltage and 8A continuous drain current in a surface mount TO-263 (D2PAK) package. This device is classified as obsolete, which necessitates identification of equivalent and substitute components for ongoing design support and procurement.

The IRF840ASTRL serves in high-voltage switching applications requiring moderate current handling and low on-state resistance. Due to its obsolete status, alternative parts with matching or superior electrical characteristics are required to maintain design continuity and ensure component availability.

Key Parameters

Parameter	Value	Unit
Drain to Source Voltage (Vdss)	500	V
Continuous Drain Current (Id) @ 25°C	8	A (Tc)
On-State Resistance (Rds On Max) @ 4.8A, 10V	850	mOhm
Gate Threshold Voltage (Vgs(th) Max) @ 250µA	4	V
Gate Charge (Qg Max) @ 10V	38	nC
Input Capacitance (Ciss Max) @ 25V	1018	pF
Power Dissipation (Max)	3.1 (Ta), 125 (Tc)	W
Operating Temperature Range	-55 to 150	°C (TJ)
Package Type	TO-263 (D2PAK)	Surface Mount
Vgs (Max)	±30	V

Substitute Part Grouping Explanation

Substitution of the IRF840ASTRL is determined by the following critical parameters:

Electrical Compatibility Criteria:

Drain to Source Voltage (Vdss): Must equal or exceed 500V
Continuous Drain Current (Id): Must equal or exceed 8A at 25°C
On-State Resistance (Rds On): Lower values indicate improved performance; maximum 850mOhm at specified conditions ensures thermal compatibility
Gate Threshold Voltage (Vgs(th)): Must remain within ±30V maximum gate voltage specification
Operating Temperature Range: Must support -55°C to 150°C junction temperature

Mechanical Compatibility Criteria:

Package Type: TO-263 (D2PAK) surface mount configuration
Pin Configuration: 2 Leads + Tab (TO-263-3)

Compliance Criteria:

RoHS Status: Active product status preferred; RoHS3 compliance required for new designs
Moisture Sensitivity Level: MSL 1 (Unlimited) acceptable

Substitute parts are grouped into two categories: parametric equivalents (identical electrical specifications) and manufacturer-recommended alternatives (enhanced performance characteristics within the same package and voltage class).

Parameter Comparison

Parameter	IRF840ASTRL	IRF840ASTRLPBF	STB11NK50ZT4	Unit
Manufacturer	Vishay Siliconix	Vishay Siliconix	STMicroelectronics	—
Product Status	Obsolete	Active	Active	—
Drain to Source Voltage (Vdss)	500	500	500	V
Continuous Drain Current (Id) @ 25°C	8	8	10	A (Tc)
On-State Resistance (Rds On Max)	850 @ 4.8A, 10V	850 @ 4.8A, 10V	520 @ 4.5A, 10V	mOhm
Gate Threshold Voltage (Vgs(th) Max)	4 @ 250µA	4 @ 250µA	4.5 @ 100µA	V
Gate Charge (Qg Max) @ 10V	38	38	68	nC
Input Capacitance (Ciss Max) @ 25V	1018	1018	1390	pF
Power Dissipation (Max)	3.1 (Ta), 125 (Tc)	3.1 (Ta), 125 (Tc)	125 (Tc)	W
Operating Temperature Range	-55 to 150	-55 to 150	-55 to 150	°C (TJ)
Package Type	TO-263 (D2PAK)	TO-263 (D2PAK)	D2PAK	Surface Mount
Vgs (Max)	±30	±30	±30	V
RoHS Status	Non-compliant	ROHS3 Compliant	ROHS3 Compliant	—
Moisture Sensitivity Level	1 (Unlimited)	1 (Unlimited)	1 (Unlimited)	—

Engineering Selection Recommendations

IRF840ASTRLPBF (Parametric Equivalent)

The IRF840ASTRLPBF is a direct parametric equivalent to the IRF840ASTRL, offering identical electrical specifications across all measured parameters. This part is manufactured by Vishay Siliconix and maintains the same 500V/8A rating, on-state resistance, and thermal characteristics. The primary distinction is product status: IRF840ASTRLPBF is active and ROHS3 compliant, whereas the original IRF840ASTRL is obsolete and non-compliant. The IRF840ASTRLPBF is supplied in Tape & Reel packaging with 3000 units in stock, providing superior availability compared to the obsolete original part.

STB11NK50ZT4 (Manufacturer-Recommended Alternative)

The STB11NK50ZT4, manufactured by STMicroelectronics, is a performance-enhanced substitute within the same voltage class and package family. This device exceeds the IRF840ASTRL specification in continuous drain current (10A versus 8A) and delivers superior on-state resistance (520mOhm versus 850mOhm), resulting in reduced power dissipation and improved thermal performance. The STB11NK50ZT4 is ROHS3 compliant and active in production with 4361 units in stock. Higher gate charge (68nC versus 38nC) and input capacitance (1390pF versus 1018pF) require verification of gate drive circuit capability in switching applications.

For new designs and procurement of obsolete IRF840ASTRL inventory, the IRF840ASTRLPBF provides direct substitution with improved compliance status. For applications requiring enhanced current handling or reduced conduction losses, the STB11NK50ZT4 offers superior performance within the same package envelope.

Frequently Asked Questions (FAQ)

Q: Can the IRF840ASTRLPBF be used as a direct replacement for the IRF840ASTRL?

A: Yes. The IRF840ASTRLPBF is a parametric equivalent with identical electrical specifications, including Vdss (500V), Id (8A), Rds On (850mOhm), and operating temperature range (-55°C to 150°C). Both devices use the TO-263 (D2PAK) package with identical pin configuration. The primary difference is product status and RoHS compliance; IRF840ASTRLPBF is active and ROHS3 compliant.

Q: What are the key differences between the IRF840ASTRL and STB11NK50ZT4?

A: Both devices share the same 500V drain-to-source voltage rating and TO-263 (D2PAK) package. The STB11NK50ZT4 provides higher continuous drain current (10A versus 8A) and lower on-state resistance (520mOhm versus 850mOhm). Gate charge is higher in the STB11NK50ZT4 (68nC versus 38nC), which may affect gate drive circuit design. Both operate across -55°C to 150°C.

Q: Is the STB11NK50ZT4 compatible with existing PCB layouts designed for the IRF840ASTRL?

A: Yes. Both devices use the TO-263 (D2PAK) surface mount package with identical pin configuration (2 Leads + Tab). PCB footprints are compatible. However, the enhanced electrical characteristics of the STB11NK50ZT4 (higher current rating and lower on-state resistance) require verification that gate drive circuits can accommodate the increased gate charge (68nC versus 38nC).

Q: What is the significance of RoHS compliance for these parts?

A: The IRF840ASTRL is RoHS non-compliant, while both IRF840ASTRLPBF and STB11NK50ZT4 are ROHS3 compliant. For applications subject to RoHS regulations or customer requirements, only the compliant alternatives are acceptable. RoHS3 compliance indicates the device meets restrictions on hazardous substances in electrical and electronic equipment.

Q: Are there packaging differences between these parts?

A: The IRF840ASTRL is supplied in standard packaging. The IRF840ASTRLPBF is supplied in Tape & Reel (TR) format, suitable for automated assembly. The STB11NK50ZT4 is supplied in Cut Tape (CT) and Digi-Reel® format. All three devices use the same TO-263 (D2PAK) component package with identical pin configuration.

Q: Can the STB11NK50ZT4 be used in applications designed for 8A continuous current?

A: Yes. The STB11NK50ZT4 is rated for 10A continuous drain current, exceeding the 8A requirement of the IRF840ASTRL. The device operates safely at 8A with improved thermal performance due to lower on-state resistance (520mOhm versus 850mOhm). Gate drive circuit capability must be verified to accommodate the higher gate charge specification.

Q: What is the moisture sensitivity level for these parts?

A: All three devices—IRF840ASTRL, IRF840ASTRLPBF, and STB11NK50ZT4—are rated MSL 1 (Unlimited), indicating no moisture sensitivity restrictions. These parts do not require special moisture control during storage or handling.

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