FQD2N50TM N-Channel MOSFET 500V 1.6A Equivalent & Substitute Parts

Part Overview

The FQD2N50TM is an N-Channel MOSFET manufactured by onsemi, rated for 500V drain-to-source voltage with 1.6A continuous drain current at 25°C. The device is housed in a TO-252-3 (DPAK) surface mount package and is classified as obsolete. Due to its obsolete status, equivalent substitute parts with matching or superior electrical and mechanical specifications are necessary for ongoing design support and production continuity.

Key Parameters

Parameter	Value	Unit
Drain-to-Source Voltage (Vdss)	500	V
Continuous Drain Current (Id) @ 25°C	1.6	A (Tc)
Drive Voltage (Max Rds On)	10	V
Rds On (Max) @ Id, Vgs	5.3	Ohm @ 800mA, 10V
Gate Threshold Voltage (Vgs(th)) (Max)	5	V @ 250µA
Gate Charge (Qg) (Max)	8	nC @ 10V
Maximum Gate Voltage (Vgs)	±30	V
Input Capacitance (Ciss) (Max)	230	pF @ 25V
Power Dissipation (Max)	2.5 (Ta), 30 (Tc)	W
Operating Temperature Range	-55 to 150	°C (TJ)
Package Type	TO-252-3 (DPAK)	Surface Mount
Moisture Sensitivity Level (MSL)	1	Unlimited

Substitute Part Grouping Explanation

Substitution of the FQD2N50TM is determined by the following critical electrical and mechanical parameters:

Electrical Compatibility Criteria:

Drain-to-Source Voltage (Vdss) must equal or exceed 500V
Continuous Drain Current (Id) must equal or exceed 1.6A at 25°C
Gate Threshold Voltage (Vgs(th)) must be compatible with 10V drive voltage
Maximum Gate Voltage (Vgs) must support ±30V operation
Operating temperature range must encompass -55°C to 150°C

Mechanical Compatibility Criteria:

Package type must be TO-252-3 (DPAK) surface mount
Moisture Sensitivity Level (MSL) must be 1 (Unlimited)
Pin configuration must match 2 Leads + Tab layout

Regulatory Compliance:

REACH Status: REACH Unaffected
ECCN: EAR99
HTSUS: 8541.29.0095

Substitute parts meeting all electrical and mechanical parameters are classified as direct equivalents. Parts exceeding the specified current or power dissipation ratings remain functionally compatible within the same application envelope.

Parameter Comparison

Parameter	FQD2N50TM (onsemi)	RDD022N50TL (Rohm)	STD3NK50ZT4 (STMicroelectronics)
Drain-to-Source Voltage (Vdss)	500V	500V	500V
Continuous Drain Current (Id) @ 25°C	1.6A (Tc)	2A (Tc)	2.3A (Tc)
Drive Voltage (Max Rds On)	10V	10V	10V
Rds On (Max) @ Id, Vgs	5.3Ω @ 800mA, 10V	5.4Ω @ 1A, 10V	3.3Ω @ 1.15A, 10V
Gate Threshold Voltage (Vgs(th)) (Max)	5V @ 250µA	4.7V @ 1mA	4.5V @ 50µA
Gate Charge (Qg) (Max)	8nC @ 10V	6.7nC @ 10V	15nC @ 10V
Maximum Gate Voltage (Vgs)	±30V	±30V	±30V
Input Capacitance (Ciss) (Max)	230pF @ 25V	168pF @ 25V	280pF @ 25V
Power Dissipation (Max)	2.5W (Ta), 30W (Tc)	20W (Tc)	45W (Tc)
Operating Temperature Range	-55°C to 150°C (TJ)	150°C (TJ)	-55°C to 150°C (TJ)
Package Type	TO-252-3 (DPAK)	TO-252-3 (DPAK)	TO-252-3 (DPAK)
Product Status	Obsolete	Active	Active
Moisture Sensitivity Level (MSL)	1 (Unlimited)	1 (Unlimited)	1 (Unlimited)
REACH Status	REACH Unaffected	REACH Unaffected	REACH Unaffected
ECCN	EAR99	EAR99	EAR99

Engineering Selection Recommendations

RDD022N50TL (Rohm Semiconductor): The RDD022N50TL meets all electrical and mechanical compatibility requirements for direct substitution. It provides 2A continuous drain current, exceeding the FQD2N50TM specification of 1.6A. The device is classified as Active product status, ensuring long-term availability and supply chain continuity. RoHS3 compliance and REACH Unaffected status confirm regulatory alignment. The lower gate charge (6.7nC versus 8nC) and reduced input capacitance (168pF versus 230pF) provide improved switching characteristics. Power dissipation is rated at 20W (Tc), supporting thermal management in the specified operating range.

STD3NK50ZT4 (STMicroelectronics): The STD3NK50ZT4 is a direct mechanical and electrical substitute with enhanced performance specifications. It delivers 2.3A continuous drain current and 45W power dissipation (Tc), providing significant margin above the FQD2N50TM requirements. The device features a 3.3Ω maximum on-resistance at 1.15A and 10V, representing a 38% improvement over the original part. Active product status and RoHS3 compliance ensure production availability and regulatory compliance. The SuperMESH™ technology platform delivers superior thermal and switching performance. Operating temperature range matches the original specification (-55°C to 150°C). Packaging is identical TO-252-3 (DPAK) surface mount configuration.

Both substitute parts are qualified for direct replacement in applications requiring 500V N-Channel MOSFET functionality with 1.6A or greater continuous drain current capability.

Frequently Asked Questions (FAQ)

Q: Can the RDD022N50TL or STD3NK50ZT4 be used as direct replacements for the FQD2N50TM?

A: Yes. Both substitute parts meet or exceed all critical electrical parameters (Vdss, Id, Vgs(th), Vgs) and share identical TO-252-3 (DPAK) surface mount packaging. Pin configuration and MSL rating are identical. No circuit modifications are required.

Q: What is the significance of the higher continuous drain current ratings in the substitute parts?

A: The RDD022N50TL (2A) and STD3NK50ZT4 (2.3A) provide current ratings above the FQD2N50TM specification (1.6A). This additional margin improves thermal performance and reduces on-resistance losses in the application, extending device lifetime and improving efficiency.

Q: How do the on-resistance specifications compare?

A: The FQD2N50TM specifies 5.3Ω maximum on-resistance at 800mA and 10V. The RDD022N50TL provides 5.4Ω at 1A and 10V, while the STD3NK50ZT4 delivers 3.3Ω at 1.15A and 10V. Lower on-resistance reduces power dissipation and heat generation in switching applications.

Q: Are there differences in gate charge between the parts?

A: Yes. The FQD2N50TM specifies 8nC gate charge at 10V. The RDD022N50TL provides 6.7nC, and the STD3NK50ZT4 provides 15nC. Lower gate charge enables faster switching transitions and reduced driver power consumption. Higher gate charge may require driver circuit adjustment in high-frequency applications.

Q: What is the impact of input capacitance differences?

A: The FQD2N50TM specifies 230pF input capacitance at 25V. The RDD022N50TL provides 168pF (27% reduction), while the STD3NK50ZT4 provides 280pF (22% increase). Lower input capacitance reduces gate drive requirements and improves switching speed. Higher input capacitance may increase driver power consumption but remains within acceptable limits for standard gate drive circuits.

Q: Do the substitute parts support the same operating temperature range?

A: The STD3NK50ZT4 supports the full operating range of -55°C to 150°C (TJ), matching the FQD2N50TM specification. The RDD022N50TL specifies a maximum junction temperature of 150°C without explicit lower temperature limit documentation. Both parts are suitable for the stated operating environment.

Q: What is the difference between power dissipation ratings?

A: The FQD2N50TM specifies 2.5W at ambient temperature (Ta) and 30W at case temperature (Tc). The RDD022N50TL provides 20W (Tc), and the STD3NK50ZT4 provides 45W (Tc). Higher power dissipation ratings indicate improved thermal performance and greater margin for continuous operation at elevated currents.

Q: Are all substitute parts RoHS compliant?

A: The STD3NK50ZT4 is explicitly RoHS3 compliant. The RDD022N50TL is RoHS3 compliant. The FQD2N50TM does not specify RoHS status. All parts maintain REACH Unaffected status and EAR99 export classification.

Q: What is the product status significance?

A: The FQD2N50TM is classified as Obsolete, indicating discontinued production and limited availability. Both substitute parts are classified as Active, ensuring ongoing manufacturing, supply chain availability, and long-term design support.

Q: Are there any package or pinout differences?

A: No. All three parts use identical TO-252-3 (DPAK) surface mount packaging with 2 Leads + Tab configuration. PCB footprints and assembly processes are interchangeable.

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