FDPF7N50 N-Channel MOSFET 500V 7A Equivalent & Substitute Parts

Part Overview

The FDPF7N50 is an N-Channel MOSFET manufactured by onsemi, rated for 500V drain-to-source voltage and 7A continuous drain current in a Through Hole TO-220F-3 package. This device is part of the UniFET™ series and is classified as obsolete. Due to its obsolete status, equivalent and substitute parts are necessary for ongoing design support, production continuity, and system maintenance applications.

Key Parameters

Parameter	Value	Unit
Drain to Source Voltage (Vdss)	500	V
Continuous Drain Current (Id) @ 25°C	7	A
Rds On (Max) @ Id, Vgs	900 mOhm @ 3.5A, 10V	Ω
Gate Threshold Voltage (Vgs(th)) @ Id	5	V @ 250µA
Gate Charge (Qg) @ Vgs	16.6	nC @ 10V
Input Capacitance (Ciss) @ Vds	940	pF @ 25V
Power Dissipation (Max)	39	W
Operating Temperature Range	-55 to 150	°C
Package Type	TO-220-3	Through Hole
FET Type	N-Channel
Technology	MOSFET (Metal Oxide)

Substitute Part Grouping Explanation

Substitution of the FDPF7N50 is determined by the following critical parameters:

Primary Substitution Criteria:

Drain to Source Voltage (Vdss): Minimum 500V
Continuous Drain Current (Id): Minimum 7A
Package Type: Through Hole TO-220 family
FET Type: N-Channel
Technology: MOSFET (Metal Oxide)
Operating Temperature Range: -55°C to 150°C minimum

Secondary Compatibility Parameters:

Gate Threshold Voltage (Vgs(th)): Within ±1V of specified value
On-State Resistance (Rds On): Lower or equivalent values acceptable
Gate Charge (Qg): Lower or equivalent values acceptable
Input Capacitance (Ciss): Lower or equivalent values acceptable

The substitute parts listed below meet or exceed the primary substitution criteria and maintain compatibility within the secondary parameters. Variations in Vdss above 500V, Id above 7A, and improved electrical characteristics (lower Rds On, Qg, Ciss) are acceptable for direct substitution in applications designed for the FDPF7N50.

Parameter Comparison

Parameter	FDPF7N50	FDPF8N50NZ	STF8NM50N	TK7A55D(STA4,Q,M)
Manufacturer	onsemi	onsemi	STMicroelectronics	Toshiba Semiconductor
Vdss (V)	500	500	500	550
Id @ 25°C (A)	7	8	5	7
Rds On (Max) @ Id, Vgs (mOhm)	900 @ 3.5A, 10V	850 @ 4A, 10V	790 @ 2.5A, 10V	1250 @ 3.5A, 10V
Vgs(th) (Max) @ Id (V)	5 @ 250µA	5 @ 250µA	4 @ 250µA	4.4 @ 1mA
Gate Charge (Qg) @ Vgs (nC)	16.6 @ 10V	18 @ 10V	14 @ 10V	16 @ 10V
Ciss (Max) @ Vds (pF)	940 @ 25V	735 @ 25V	364 @ 50V	700 @ 25V
Power Dissipation (Max) (W)	39	40.3	20	35
Operating Temperature (°C)	-55 to 150	-55 to 150	-55 to 150	-55 to 150
Package	TO-220F-3	TO-220F-3	TO-220FP	TO-220SIS
Product Status	Obsolete	Obsolete	Active	Active
RoHS Status	Not specified	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant

Engineering Selection Recommendations

FDPF8N50NZ (onsemi): This part is the closest electrical equivalent to the FDPF7N50, offering identical Vdss (500V) and superior continuous drain current (8A vs. 7A). The Rds On is improved at 850 mOhm, and input capacitance is reduced to 735 pF. Both devices share the same TO-220F-3 package and UniFET™ series designation. However, FDPF8N50NZ is also classified as obsolete. This substitute is suitable for direct replacement in applications where higher current capability is acceptable.

STF8NM50N (STMicroelectronics): This part maintains the 500V Vdss rating and operates within the required temperature range. It features superior on-state resistance (790 mOhm) and significantly lower input capacitance (364 pF). The continuous drain current is rated at 5A, which is lower than the FDPF7N50 specification. STF8NM50N is classified as active product status with ROHS3 compliance, providing long-term availability. This substitute is suitable for applications where the 5A current rating is sufficient and improved switching characteristics are beneficial.

TK7A55D(STA4,Q,M) (Toshiba Semiconductor): This part exceeds the Vdss requirement at 550V and matches the 7A continuous drain current rating. It is classified as active product status with ROHS3 compliance. The gate threshold voltage is lower at 4.4V, and gate charge is comparable at 16 nC. The on-state resistance is higher at 1250 mOhm, which may impact thermal performance in high-current applications. The TO-220SIS package is mechanically compatible with TO-220 footprints. This substitute is suitable for applications requiring higher voltage margin and long-term supply assurance.

Recommendation Priority:

STF8NM50N for new designs requiring active product status and improved electrical characteristics
FDPF8N50NZ for direct replacement where onsemi UniFET™ series continuity is required
TK7A55D(STA4,Q,M) for applications requiring higher voltage rating and active product availability

Frequently Asked Questions (FAQ)

Q: Can FDPF8N50NZ be used as a direct replacement for FDPF7N50?

A: Yes. Both devices share identical Vdss (500V), matching gate threshold voltage (5V @ 250µA), comparable gate charge (18 nC vs. 16.6 nC), and the same TO-220F-3 package. FDPF8N50NZ provides higher continuous drain current (8A vs. 7A) and improved on-state resistance (850 mOhm vs. 900 mOhm). Pin-to-pin compatibility is maintained.

Q: Is STF8NM50N suitable for applications requiring 7A continuous current?

A: STF8NM50N is rated for 5A continuous drain current, which is below the FDPF7N50 specification of 7A. This substitute is suitable only for applications where the actual operating current does not exceed 5A. Thermal analysis is required to confirm adequate margin in the specific application.

Q: What are the package differences between the substitute parts?

A: FDPF7N50 and FDPF8N50NZ use TO-220F-3 packages. STF8NM50N uses TO-220FP, and TK7A55D(STA4,Q,M) uses TO-220SIS. All three substitute packages are mechanically compatible with standard TO-220 footprints and pin assignments. Verify PCB layout clearances for thermal management differences.

Q: Why is TK7A55D rated at 550V instead of 500V?

A: TK7A55D is designed for higher voltage applications and exceeds the FDPF7N50 Vdss specification. The 550V rating provides additional voltage margin and is fully compatible with 500V system designs. No derating is required.

Q: Are all substitute parts RoHS compliant?

A: FDPF8N50NZ, STF8NM50N, and TK7A55D(STA4,Q,M) are all ROHS3 compliant. The original FDPF7N50 RoHS status is not specified in the provided data. For applications requiring RoHS compliance, the substitute parts provide documented compliance.

Q: What is the impact of different Rds On values on circuit performance?

A: Lower Rds On values reduce conduction losses and heat dissipation. STF8NM50N (790 mOhm) and FDPF8N50NZ (850 mOhm) provide improved efficiency compared to FDPF7N50 (900 mOhm). TK7A55D (1250 mOhm) results in higher conduction losses. Thermal design calculations should account for these differences in high-current or high-frequency applications.

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

A: Electrical interchangeability is confirmed for all listed substitutes within the specified parameter ranges. Mechanical compatibility is maintained across all TO-220 package variants. However, thermal management design and PCB layout may require adjustment based on the specific substitute selected and its power dissipation characteristics.

Q: Which substitute offers the best long-term availability?

A: STF8NM50N and TK7A55D(STA4,Q,M) are both classified as active product status, ensuring long-term availability and supply continuity. FDPF8N50NZ is obsolete, similar to the original FDPF7N50. For new designs, active-status parts are recommended.

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