FQP9N50 N-Channel MOSFET 500V 9A Equivalent & Substitute Parts

Part Overview

The FQP9N50 is an N-Channel MOSFET manufactured by onsemi, rated for 500V drain-to-source voltage with 9A continuous drain current at 25°C. This device is packaged in TO-220-3 through-hole configuration and is classified as Obsolete product status. Due to its obsolete classification, equivalent substitute parts from active product lines are necessary for new designs and ongoing production requirements. Substitute parts must maintain electrical compatibility across voltage rating, current capacity, and thermal characteristics while accommodating the through-hole TO-220 package standard.

Key Parameters

Parameter	FQP9N50	Unit
Drain-to-Source Voltage (Vdss)	500	V
Continuous Drain Current (Id) @ 25°C	9	A
On-State Resistance (Rds On) @ 4.5A, 10V	730	mOhm
Gate Threshold Voltage (Vgs(th)) @ 250µA	5	V
Gate Charge (Qg) @ 10V	36	nC
Input Capacitance (Ciss) @ 25V	1450	pF
Power Dissipation (Max)	147	W
Operating Temperature Range	-55 to 150	°C
Package Type	TO-220-3	—
Mounting Type	Through Hole	—

Substitute Part Grouping Explanation

Substitute parts for the FQP9N50 are selected based on strict electrical parameter compatibility within the N-Channel MOSFET category. The primary substitution criteria are:

Critical Parameters for Substitution:

Drain-to-Source Voltage (Vdss): Must equal or exceed 500V
Continuous Drain Current (Id): Must equal or exceed 9A at 25°C
Package Type: Must be TO-220-3 through-hole configuration
FET Technology: N-Channel MOSFET (Metal Oxide)
Operating Temperature Range: Must support -55°C to 150°C minimum

Secondary Compatibility Parameters:

On-State Resistance (Rds On): Lower values indicate improved performance
Gate Charge (Qg): Lower values reduce switching losses
Input Capacitance (Ciss): Affects gate drive requirements
Power Dissipation: Thermal management capability

Substitute parts are grouped into two categories based on electrical characteristics:

Category 1 - Direct Voltage/Current Match (500V, 9A): AOT9N50 (Alpha & Omega Semiconductor) maintains identical 500V/9A ratings with comparable thermal performance.

Category 2 - Enhanced Performance (500V, 10A+): STP11NK50Z (STMicroelectronics) exceeds the 9A requirement with 10A continuous current and improved on-state resistance, providing superior thermal characteristics.

Category 3 - Reduced Current Rating (500V, 8A): AOT8N50 (Alpha & Omega Semiconductor) operates at 500V with 8A continuous current, suitable for applications with lower current demands.

Category 4 - Reduced Voltage Rating (400V, 8A): AOT9N40 (Alpha & Omega Semiconductor) operates at 400V with 8A continuous current, applicable only to circuits with maximum operating voltages below 400V.

Category 5 - Reduced Current Rating (500V, 5A): STP8NM50N (STMicroelectronics) operates at 500V with 5A continuous current, suitable for low-current applications only.

Parameter Comparison

Parameter	FQP9N50	AOT8N50	AOT9N40	AOT9N50	STP11NK50Z	STP8NM50N	Unit
Manufacturer	onsemi	Alpha & Omega	Alpha & Omega	Alpha & Omega	STMicroelectronics	STMicroelectronics	—
Vdss	500	500	400	500	500	500	V
Id @ 25°C	9	8	8	9	10	5	A
Rds On @ 10V	730	850	800	850	520	790	mOhm
Vgs(th) @ 250µA	5	4.5	4.5	4.5	4.5	4	V
Qg @ 10V	36	28	16	28	68	14	nC
Ciss @ 25V	1450	1042	760	1042	1390	364	pF
Power Dissipation (Max)	147	192	132	192	125	45	W
Operating Temp Range	-55 to 150	-55 to 150	-55 to 150	-55 to 150	-55 to 150	to 150	°C
Package	TO-220-3	TO-220	TO-220	TO-220	TO-220	TO-220	—
Product Status	Obsolete	Not For New Designs	Active	Not For New Designs	Active	Active	—
RoHS Status	Not specified	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant	—

Engineering Selection Recommendations

For Direct Replacement in Active Production:

STP11NK50Z (STMicroelectronics) is the recommended primary substitute. This device maintains 500V voltage rating with enhanced 10A continuous current capability, exceeding the FQP9N50 specification. The STP11NK50Z carries Active product status with ROHS3 compliance, ensuring long-term availability and regulatory alignment. Superior on-state resistance (520 mOhm vs. 730 mOhm) provides improved thermal performance and reduced power dissipation in high-frequency switching applications.

For Cost-Optimized Substitution:

AOT9N50 (Alpha & Omega Semiconductor) provides electrical equivalence with identical 500V/9A ratings. This part carries ROHS3 compliance but is classified as Not For New Designs. Inventory availability is confirmed at 3,846 pieces. This option is suitable for legacy system maintenance and retrofit applications where design changes are not feasible.

For Reduced Current Applications:

AOT8N50 (Alpha & Omega Semiconductor) operates at 500V with 8A continuous current and is classified as Not For New Designs. This substitute is applicable only when circuit requirements permit reduced current capacity. ROHS3 compliance is confirmed.

For Voltage-Reduced Applications:

AOT9N40 (Alpha & Omega Semiconductor) operates at 400V with 8A continuous current and carries Active product status with ROHS3 compliance. This substitute is applicable only to circuits with maximum operating voltages not exceeding 400V.

Not Recommended for Primary Substitution:

STP8NM50N (STMicroelectronics) operates at 500V with only 5A continuous current, significantly below the FQP9N50 specification. This part is suitable only for applications with substantially reduced current requirements and is not recommended as a general substitute.

Frequently Asked Questions (FAQ)

Q: Can AOT9N50 be used as a direct replacement for FQP9N50?

A: AOT9N50 maintains identical electrical specifications (500V, 9A) and TO-220 package configuration. However, AOT9N50 carries Not For New Designs status. It is suitable for legacy system maintenance but not recommended for new product development.

Q: What is the primary advantage of STP11NK50Z over FQP9N50?

A: STP11NK50Z provides 10A continuous current (exceeding the 9A requirement) with significantly lower on-state resistance (520 mOhm vs. 730 mOhm). This results in reduced power dissipation and improved thermal performance. STP11NK50Z carries Active product status with ROHS3 compliance, ensuring long-term supply availability.

Q: Can STP8NM50N substitute for FQP9N50?

A: STP8NM50N operates at 500V but with only 5A continuous current, which is below the FQP9N50 specification of 9A. This part is not suitable as a general substitute and should be used only in applications with reduced current requirements.

Q: Is AOT9N40 compatible with FQP9N50 circuits?

A: AOT9N40 operates at 400V maximum voltage, which is lower than the FQP9N50 rating of 500V. This substitute is compatible only with circuits designed for maximum operating voltages not exceeding 400V. It is not suitable for applications requiring full 500V capability.

Q: What compliance certifications should I verify for substitute parts?

A: All recommended substitute parts carry ROHS3 compliance and REACH Unaffected status. Verify that your application requirements align with these certifications before final part selection.

Q: How do gate charge differences affect circuit design?

A: Gate charge (Qg) values range from 14 nC (STP8NM50N) to 68 nC (STP11NK50Z). Higher gate charge requires greater gate drive current and energy. Circuit gate driver designs must accommodate the specific gate charge of the selected substitute part.

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

A: All substitute parts use TO-220 through-hole packaging, which is mechanically compatible with FQP9N50 TO-220-3 footprints. Verify PCB layout compatibility with your specific board design before implementation.

Q: What is the significance of Product Status classifications?

A: Active status indicates ongoing manufacturer support and long-term availability. Not For New Designs indicates limited future support. Obsolete status (FQP9N50) indicates discontinued production. For new designs, select parts with Active status to ensure supply chain continuity.

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