FQB6N50TM Equivalent & Substitute Parts

Part Overview

The FQB6N50TM is an N-Channel MOSFET manufactured by onsemi, rated for 500V drain-to-source voltage with a continuous drain current of 5.5A at 25°C. This device is housed in a Surface Mount TO-263 (D2PAK) package and is classified as obsolete. The part operates across a temperature range of -55°C to 150°C and is part of the QFET® series. Due to its obsolete status, identifying equivalent substitute parts is necessary for ongoing design support, production continuity, and component sourcing.

Key Parameters

Parameter	Value	Unit
Drain to Source Voltage (Vdss)	500	V
Continuous Drain Current (Id) @ 25°C	5.5	A
Rds On (Max) @ Id, Vgs	1.3	Ohm @ 2.8A, 10V
Gate Charge (Qg) (Max) @ Vgs	22	nC @ 10V
Input Capacitance (Ciss) (Max) @ Vds	790	pF @ 25V
Power Dissipation (Max)	130	W (Tc)
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 FQB6N50TM is determined by the following critical electrical and mechanical parameters:

Voltage Rating: The substitute part must maintain a Drain to Source Voltage (Vdss) of 500V to ensure compatibility with the original circuit design and voltage stress conditions.

Package Type: The substitute must use the TO-263 (D2PAK) Surface Mount package to ensure mechanical and thermal compatibility with existing PCB layouts and assembly processes.

FET Technology: Both the main part and substitute must be N-Channel MOSFETs to maintain functional equivalence in circuit operation.

Operating Temperature Range: The substitute must support the full operating temperature range of -55°C to 150°C (TJ) to ensure reliability across all specified conditions.

Current Rating: While the FQB6N50TM is rated for 5.5A continuous drain current, substitute parts with lower current ratings may be considered for applications where the full current capacity is not required, provided all other parameters are met.

The IXTA3N50D2 from IXYS meets the voltage rating, package type, FET technology, and operating temperature requirements. However, its continuous drain current rating of 3A is lower than the original part's 5.5A specification.

Parameter Comparison

Parameter	FQB6N50TM (onsemi)	IXTA3N50D2 (IXYS)	Unit
Drain to Source Voltage (Vdss)	500	500	V
Continuous Drain Current (Id) @ 25°C	5.5	3	A
Rds On (Max) @ Id, Vgs	1.3 @ 2.8A, 10V	1.5 @ 1.5A, 0V	Ohm
Gate Charge (Qg) (Max) @ Vgs	22 @ 10V	40 @ 5V	nC
Input Capacitance (Ciss) (Max) @ Vds	790 @ 25V	1070 @ 25V	pF
Power Dissipation (Max)	130	125	W (Tc)
Operating Temperature Range	-55 to 150	-55 to 150	°C (TJ)
Package Type	TO-263 (D2PAK)	TO-263AA	Surface Mount
Vgs (Max)	±30	±20	V
Product Status	Obsolete	Active

Engineering Selection Recommendations

For Direct Replacement: The IXTA3N50D2 is suitable as a substitute for the FQB6N50TM in applications where the continuous drain current requirement does not exceed 3A. Both devices share identical voltage ratings (500V Vdss), compatible package types (TO-263 D2PAK variants), and matching operating temperature ranges (-55°C to 150°C). The IXTA3N50D2 holds Active product status, ensuring ongoing availability and supply chain continuity compared to the obsolete FQB6N50TM.

Compliance Considerations: Both parts carry REACH Unaffected status and EAR99 ECCN classification. The IXTA3N50D2 is RoHS3 Compliant, providing additional environmental compliance assurance. Both devices maintain Moisture Sensitivity Level 1 (Unlimited), indicating no moisture-related handling restrictions.

Current Derating: Applications requiring the full 5.5A continuous drain current of the FQB6N50TM cannot use the IXTA3N50D2 without circuit redesign or thermal management modifications. The 3A rating of the substitute represents a 45% reduction in current capacity.

Gate Charge and Capacitance: The IXTA3N50D2 exhibits higher gate charge (40 nC vs. 22 nC) and input capacitance (1070 pF vs. 790 pF), which may affect switching speed and gate drive requirements in high-frequency applications.

Frequently Asked Questions (FAQ)

Q: Can the IXTA3N50D2 directly replace the FQB6N50TM in all applications?

A: Direct replacement is possible only in applications where the continuous drain current does not exceed 3A. The IXTA3N50D2 is rated for 3A continuous drain current, compared to the FQB6N50TM's 5.5A rating. Circuit analysis is required to confirm current requirements before substitution.

Q: Are the package types compatible between these two parts?

A: Both parts use TO-263 D2PAK Surface Mount packages. The FQB6N50TM uses TO-263-3 (D2PAK with 2 Leads + Tab), and the IXTA3N50D2 uses TO-263AA. These variants are mechanically compatible with standard TO-263 PCB footprints.

Q: What is the difference in gate charge between these parts?

A: The FQB6N50TM has a maximum gate charge of 22 nC at 10V, while the IXTA3N50D2 has 40 nC at 5V. Higher gate charge requires greater gate drive energy and may increase switching losses in high-frequency circuits.

Q: Do both parts support the same voltage range?

A: Both parts are rated for 500V Drain to Source Voltage (Vdss) and support identical operating temperature ranges of -55°C to 150°C. However, the FQB6N50TM supports a maximum gate voltage of ±30V, while the IXTA3N50D2 supports ±20V.

Q: What is the product status difference, and why does it matter?

A: The FQB6N50TM is classified as Obsolete, indicating it is no longer in active production. The IXTA3N50D2 is Active, ensuring continued availability, technical support, and supply chain reliability for new designs and production runs.

Q: Are there any compliance or certification differences?

A: Both parts are REACH Unaffected and carry EAR99 ECCN classification. The IXTA3N50D2 is additionally RoHS3 Compliant, providing enhanced environmental compliance certification. Both maintain Moisture Sensitivity Level 1 (Unlimited).

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