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Home > Products > Discrete Semiconductor Products > Transistors > FETs, MOSFETs > FETs, MOSFETs

STMicroelectronics STF9NM50N

Name: STF9NM50N
Brand: STMicroelectronics
SKU: STF9NM50N
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: STF9NM50N

Manufacturer:: STMicroelectronics

Category:: FETs, MOSFETs

Package:: TO-220-3 Full Pack

Datasheet:: STF9NM50N.pdf

Description:: MOSFET N-CH 500V 5A TO220FP

Quantity:: RFQ Add To RFQ list

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Inventory:6,797

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Product details

Overview

STF9NM50N from STMicroelectronics is an N-channel 500 V, 7.5 A, 0.47 Ω (typ) MDmesh™ II Power MOSFET in TO-220FP package, designed for high-efficiency flyback and resonant SMPS primary-side switching. It features 100% avalanche tested ruggedness, low gate charge (20 nC), and optimized capacitance profile (Ciss = 570 pF) for reduced switching losses in 65–100 kHz converters.

For engineers reviewing the STF9NM50N datasheet, STF9NM50N pinout, STF9NM50N application, or STF9NM50N equivalent, key selection criteria include R_DS(on) at 10 V drive, safe operating area under 400 V inductive loads, thermal resistance (R_thj-case = 5 °C/W), and diode recovery performance (t_rr = 280 ns @ T_j = 25°C).

Technical Context

This device implements ST's second-generation MDmesh™ vertical structure with strip layout, enabling ultra-low R_DS(on) × Q_g figure-of-merit (0.47 Ω × 20 nC). Its gate threshold voltage (2–4 V) ensures robust noise immunity while supporting standard 10 V gate drivers.

The integrated source-drain diode supports synchronous rectification and ZVS operation, with verified reverse recovery characteristics (Q_rr = 2 µC, I_RRM = 14 A) under 100 V, 100 A/µs conditions at 25°C and 150°C junction temperatures.

Key Specifications

Parameter	Value and Actual Design Meaning
V_DSS	500 V - Withstands 400 V DC bus with 20% margin in offline SMPS designs
R_DS(on)	0.47 Ω (typ) @ V_GS = 10 V - Enables <1.8 W conduction loss at 7.5 A continuous drain current
Q_g	20 nC - Reduces gate drive power and enables use with low-current 10 V controllers
t_r/t_f	16 ns / 19 ns - Supports clean 100 kHz switching with minimal overlap loss
R_thj-case	5 °C/W - Allows 25 W dissipation with ≤125°C case temperature rise (T_j ≤ 150°C)
E_AS	150 mJ - Sustains unclamped inductive switching events without failure
C_iss	570 pF - Minimizes Miller effect and improves dv/dt immunity in high-side configurations

Pinout & Package

STF9NM50N uses the TO-220FP (Full-Pak) package: insulated plastic housing with internal isolation between drain tab and mounting surface, rated for 2500 V_RMS insulation withstand voltage. The package provides enhanced creepage/clearance for reinforced isolation in AC-DC adapters.

Pin/Terminal	Circuit Role	Design Meaning
1 (Source)	Power return path for load current	Low-inductance connection to ground plane; ties to source of external driver bootstrap circuit
2 (Gate)	Control input for channel modulation	High-impedance node requiring <100 nA leakage control; sensitive to ESD and ringing
3 (Drain)	Main high-voltage power terminal	Internally connected to metal tab; electrically isolated from heatsink via insulating pad in TO-220FP

Key Features

Feature	Design Value
100% Unclamped Inductive Avalanche Tested	Guarantees single-pulse energy handling up to 150 mJ without parameter shift or failure
Low C_oss / C_rss Ratio	C_oss = 46 pF, C_rss = 6 pF → 7.7:1 ratio improves ZVS transition efficiency in LLC converters
Optimized Body Diode Recovery	t_rr = 280 ns @ 25°C, Q_rr = 2 µC - Reduces diode-induced switching loss and EMI in hard-switched topologies
ECOPACK® Lead-Free Construction	Complies with JEDEC JESD97 marking; RoHS-compliant second-level interconnect with SnAgCu finish
Enhanced dv/dt Immunity	Rated 35 V/ns during turn-off - Resists false triggering in noisy high-voltage environments

Applications

AC-DC Adapter Primary Switch

Industrial LED Driver Stage

Use Scenario: 65 W universal-input offline flyback converter powering USB-C PD chargers.

IC Role / Device Role / Timing Role: High-side main switch controlling primary current flow and energy transfer timing.

Use Value: 0.47 Ω R_DS(on) and 20 nC Q_g enable >90% efficiency at full load while maintaining thermal headroom on compact PCB heatsinks.

Use Scenario: Constant-current 100 W LED driver for street lighting with active PFC front-end.

IC Role / Device Role / Timing Role: Primary-side switch in two-switch forward or asymmetrical half-bridge topology.

Use Value: 500 V rating and 150 mJ E_AS ensure reliability during line surges and output short-circuit events.

Server PSU LLC Resonant Switch

Industrial Motor Drive Inverter Leg

Use Scenario: 500 W server power supply using LLC resonant converter with variable frequency control.

IC Role / Device Role / Timing Role: Half-bridge switch operating in zero-voltage switching mode above resonance.

Use Value: Low C_rss/C_iss ratio minimizes capacitive turn-on loss and improves light-load regulation stability.

Use Scenario: 3 kW three-phase inverter for HVAC compressor drive with discrete IGBT replacement.

IC Role / Device Role / Timing Role: High-voltage leg switch in 3-phase inverter bridge handling 400 V DC bus.

Use Value: 100% avalanche rating and 5 °C/W R_thj-case support intermittent overload without derating in forced-air-cooled enclosures.

Equivalent & Alternatives

The following parts are listed as comparable options for similar high-voltage power switching applications.

Alternative Part	Technical Difference	Application Difference	Selection Advice
STP9NM50N	Same die, TO-220 (non-isolated tab); R_thj-case = 1.78 °C/W vs. 5 °C/W	Requires insulating washer for chassis-grounded heatsinks; higher thermal performance in direct-mount setups	Select when mechanical isolation is handled externally and lower thermal resistance is critical
FQP9N50C	500 V, 9 A, R_DS(on) = 0.55 Ω; no avalanche rating; C_iss = 620 pF	Lacks 100% avalanche test; higher Q_g (25 nC); less suitable for unclamped inductive loads	Acceptable only in cost-sensitive, non-safety-critical designs with tight gate drive capability

Compared with STP9NM50N, STF9NM50N trades 3.2 °C/W higher thermal resistance for built-in isolation-critical for double-insulated AC-DC systems-while matching all electrical specs. Against FQP9N50C, it adds guaranteed avalanche ruggedness and tighter capacitance control at modest cost premium.

Availability

STF9NM50N is available at Aetrix Electronics and suitable for AC-DC adapters, industrial LED drivers, and server power supplies requiring stable component supply across multi-year production cycles.

Supply support for STF9NM50N includes scheduled delivery planning, volume procurement assistance, BOM continuity management, traceable sourcing, and lifecycle availability coordination for OEM customers, industrial embedded developers, connected-device designers, and electronics production programs.

Manufacturer

STMicroelectronics is a global semiconductor leader headquartered in Geneva, specializing in power, analog, MCU, and sensor technologies for industrial, automotive, and consumer markets.

This device belongs to ST's MDmesh™ II Power MOSFET product line, engineered specifically for high-efficiency, high-reliability offline SMPS and resonant converter primary-side switching where low R_DS(on) × Q_g and rugged avalanche performance are essential.

FAQ

What is the maximum continuous drain current at 100°C case temperature?

The STF9NM50N supports 5 A continuous drain current at T_C = 100°C, as specified in Table 1 of the datasheet. This derating reflects thermal limits of the TO-220FP package (R_thj-case = 5 °C/W) and ensures junction temperature remains ≤150°C under sustained load.

Does STF9NM50N require a gate resistor for reliable operation?

Yes-a gate resistor (typically 4.7 Ω to 22 Ω) is required to dampen ringing, limit peak gate current, and control switching speed. The datasheet specifies t_d(on), t_r, t_d(off), and t_f values measured with R_G = 4.7 Ω, confirming its role in defining timing behavior and EMI profile.

Can STF9NM50N replace STP9NM50N in existing designs?

Electrically yes, but mechanically no without layout revision: STF9NM50N uses TO-220FP (isolated tab), whereas STP9NM50N uses standard TO-220 (conductive tab). Direct replacement requires verifying heatsink isolation, creepage distance, and thermal interface design to accommodate the higher R_thj-case.

Is STF9NM50N suitable for use in automotive applications?

No-STF9NM50N is not qualified to AEC-Q101 and lacks automotive-grade screening, temperature range extension (−40°C to 175°C), or PPAP documentation. ST recommends dedicated automotive MOSFETs such as STL9N50M5 for under-hood or battery-management use cases.

STF9NM50N Specifications

Product attributes: Attribute value

Manufacturer:: STMicroelectronics

Series:: MDmesh™

Package/Case:: TO-220-3 Full Pack

Packaging:: Tube

Product Status:: Obsolete

FET Type:: N-Channel

Technology:: MOSFET (Metal Oxide)

Drain to Source Voltage (Vdss):: 500 V

Current - Continuous Drain (Id) @ 25°C:: 5A (Tc)

Drive Voltage (Max Rds On, Min Rds On):: 10V

Rds On (Max) @ Id, Vgs:: 560mOhm @ 3.7A, 10V

Vgs(th) (Max) @ Id:: 4V @ 250µA

Gate Charge (Qg) (Max) @ Vgs:: 20 nC @ 10 V

Vgs (Max):: ±25V

Input Capacitance (Ciss) (Max) @ Vds:: 570 pF @ 50 V

FET Feature:: -

Power Dissipation (Max):: 25W (Tc)

Operating Temperature:: 150°C (TJ)

Grade:: -

Qualification:: -

Mounting Type:: Through Hole

Supplier Device Package:: TO-220FP

STF9NM50N FAQ

1.How can I place an order for STF9NM50N through Aetrix?

Please submit a Request for Quotation (RFQ) for STF9NM50N on Aetrix. Our sales agent will provide a competitive quotation and guide you through the order confirmation once you accept the terms.

2.Are the price and stock information for STF9NM50N reliable?

The price and inventory of STF9NM50N are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for STF9NM50N is usually 5 days.

3.What payment methods are accepted for STF9NM50N?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for STF9NM50N transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for STF9NM50N?

STF9NM50N orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your STF9NM50N order is processed, you will receive an email with the shipment details and tracking number.

Note: Tracking information may take up to 24 hours to appear. Express delivery typically takes 3–5 business days.

5.How can I obtain technical support or documentation for STF9NM50N?

For technical support, including STF9NM50N datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your STF9NM50N requirements.

6.How does Aetrix verify that STF9NM50N is sourced from the original manufacturer or authorized distributors?

All STF9NM50N products on Aetrix are procured from qualified distributors and authorized channels. Our dedicated quality assurance team conducts strict verification, including traceability checks and, if necessary, third-party testing. This ensures that STF9NM50N meets industry standards.

7.What is the process for return or replacement of STF9NM50N?

All STF9NM50N units undergo pre-shipment inspection (PSI). If there is an issue with STF9NM50N, returns or replacements are accepted under the following conditions:

1.Quantity discrepancies, incorrect items, or visible external defects (such as breakage or corrosion), acknowledged by Aetrix.

2.The issue is reported within 90 days of delivery.

3.The STF9NM50N part is unused and in its original packaging.

Return procedure for STF9NM50N:

1.Submit a request within 90 days.

2.Obtain a Return Material Authorization (RMA) from Aetrix.

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