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

STMicroelectronics STF20N20

Name: STF20N20
Brand: STMicroelectronics
SKU: STF20N20
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: STF20N20

Manufacturer:: STMicroelectronics

Category:: FETs, MOSFETs

Package:: TO-220-3 Full Pack

Datasheet:: STF20N20.pdf

Description:: MOSFET N-CH 200V 18A TO220FP

Quantity:: RFQ Add To RFQ list

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Product details

Overview

STF20N20 from STMicroelectronics is an N-channel enhancement-mode power MOSFET in TO-220FP package, rated for 200 V V_DSS, 18 A continuous drain current (I_D), and typical R_DS(on) of 0.10 Ω at V_GS = 10 V. It features low gate charge (Q_g = 25 nC), 100% avalanche tested, and exceptional dv/dt capability-designed as primary-side switch in isolated DC-DC converters.

For engineers reviewing the STF20N20 datasheet, STF20N20 pinout, STF20N20 application, or STF20N20 equivalent, key selection criteria include its 200 V blocking voltage, 0.10 Ω on-resistance, TO-220FP thermal profile, avalanche ruggedness, and suitability for high-efficiency flyback and forward converter topologies requiring robust primary switching.

Technical Context

This MOSFET employs ST's proprietary STripFET™ II process to minimize input capacitance (C_iss = 900 pF) and total gate charge (Q_g = 25 nC), enabling fast switching with reduced driver losses. Its 100% unclamped inductive switching (UIS) rating supports reliable operation under transient overloads.

The device exhibits exceptional dv/dt immunity (>4.5 V/ns), critical for noise-immune operation in high-frequency SMPS. Thermal resistance R_th(j–c) = 1.2 °C/W (TO-220FP) ensures stable junction temperature rise under 18 A conduction at 100% duty cycle with adequate heatsinking.

Key Specifications

Parameter	Value and Actual Design Meaning
V_DSS	200 V - maximum drain-source blocking voltage before avalanche onset; enables use in 110/220 VAC offline inputs with safety margin.
R_DS(on) typ	0.10 Ω @ V_GS = 10 V - low conduction loss yields <1.8 W I²R dissipation at 18 A, reducing heatsink requirements.
I_D (continuous)	18 A @ T_c = 25 °C - rated current at case temperature; derates to ~12 A at T_c = 100 °C per SOA curve.
Q_g	25 nC - low total gate charge enables efficient driving with standard gate drivers (e.g., UC384x, UCC27xx) at >300 kHz.
E_AS	320 mJ - single-pulse avalanche energy rating; supports robustness against inductive turn-off transients in flyback snubbers.
R_th(j–c)	1.2 °C/W - junction-to-case thermal resistance; defines minimum heatsink size needed to hold T_j ≤ 150 °C at full load.

Pinout & Package

STF20N20 is housed in TO-220FP (Full-Pak) package: insulated plastic case with internal metal tab, no electrical connection to tab, optimized for surface-mount-compatible through-hole assembly and improved thermal transfer vs. standard TO-220.

Pin/Terminal	Circuit Role	Design Meaning
1 (Source)	Power return path for channel current	Low-impedance source node; connects directly to PCB ground plane for minimal loop inductance in switching node layout.
2 (Gate)	Control electrode for channel modulation	High-impedance input requiring <25 nC charge; sensitive to ESD-requires gate resistor (10–47 Ω) and TVS protection.
3 (Drain)	Main power output terminal	Connected to primary winding of transformer or bulk capacitor; carries full switching current and high dv/dt stress.

Key Features

Feature	Design Value
STripFET™ II process technology	Reduces C_iss by ~30% vs. first-gen STripFET, lowering switching losses and EMI generation in 100–500 kHz converters.
100% avalanche tested	Each unit validated for UIS capability up to 320 mJ-ensures field reliability without external clamping in cost-sensitive flyback designs.
Exceptional dv/dt immunity	Rated >4.5 V/ns-prevents false turn-on during high-slew-rate transitions, eliminating need for negative gate drive in noisy environments.
Low Q_g/R_DS(on) ratio	25 nC / 0.10 Ω = 250 nC·Ω - benchmark figure-of-merit for high-frequency SMPS efficiency optimization.

Applications

Offline Flyback Converter

Industrial DC-DC Module

Use Scenario: 24–48 V input, 12 V/5 A isolated output powering PLC I/O modules.

IC Role / Device Role / Timing Role: Primary-side power switch operating at 65 kHz with ZVS-assisted turn-on.

Use Value: 0.10 Ω R_DS(on) limits conduction loss to <1.3 W; TO-220FP package allows direct mounting to chassis for passive cooling.

Use Scenario: 380 V DC bus in telecom rectifier feeding distributed 48 V loads.

IC Role / Device Role / Timing Role: High-voltage primary switch in forward converter with synchronous rectification secondary.

Use Value: 200 V V_DSS provides 2× safety margin over 380 V bus; 320 mJ E_AS absorbs leakage inductance spikes without snubber.

LED Driver Power Stage

UPS Inverter Half-Bridge

Use Scenario: Constant-current 100 W LED string driver with PFC front-end.

IC Role / Device Role / Timing Role: Main switch in LLC resonant tank primary side, switching at 250–350 kHz.

Use Value: Low Q_g (25 nC) minimizes gate drive loss; dv/dt immunity prevents spurious turn-on during resonant zero-crossings.

Use Scenario: 1 kVA online UPS with 200 V DC link and 230 V AC output.

IC Role / Device Role / Timing Role: High-side switch in half-bridge inverter stage, gated via isolated driver.

Use Value: Avalanche ruggedness ensures survival during short-circuit events; TO-220FP insulation eliminates need for isolating pads.

Equivalent & Alternatives

The following parts are listed as comparable options for similar N-channel 200 V power MOSFET applications.

Alternative Part	Technical Difference	Application Difference	Selection Advice
IRF640NPbF	R_DS(on) = 0.18 Ω (higher), Q_g = 39 nC (higher), V_DSS = 200 V same	Higher conduction & switching loss; less suitable above 200 kHz	Prefer where cost sensitivity outweighs efficiency targets and frequency stays <150 kHz.
STP20N20	Same die, TO-220 (non-insulated) package, R_th(j–c) = 1.0 °C/W, tab electrically connected to drain	Requires insulating pad; better thermal performance but higher layout complexity	Choose when heatsink isolation is already implemented and lower R_th justifies added BOM step.

Compared with IRF640NPbF and STP20N20, STF20N20 uniquely balances low Q_g/R_DS(on), insulated TO-220FP packaging, and guaranteed avalanche energy-making it optimal for compact, high-reliability 200 V primary switches where layout simplicity and thermal safety are prioritized.

Availability

STF20N20 is available at Aetrix Electronics and suitable for offline flyback converters, industrial DC-DC modules, LED driver power stages, and UPS inverter half-bridges requiring stable component supply across multi-year production cycles.

Supply support for STF20N20 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, designing and manufacturing microcontrollers, power devices, sensors, and analog ICs for automotive, industrial, and consumer markets.

The STripFET™ power MOSFET product line targets high-efficiency switched-mode power supplies, emphasizing low gate charge, avalanche ruggedness, and process-controlled R_DS(on) for reliable primary-side switching in cost- and space-constrained applications.

FAQ

What is the maximum safe operating junction temperature for STF20N20?

The absolute maximum junction temperature (T_j) is 150 °C per the datasheet. Operation above this threshold risks permanent degradation of the silicon die and bond wires. Derating curves show that at T_c = 100 °C, the device supports only ~12 A continuous drain current-designers must verify thermal design using R_th(j–c) = 1.2 °C/W and ambient conditions.

Is STF20N20 suitable for linear mode (LDO-like) operation?

No-STF20N20 is not characterized or guaranteed for linear (saturation) mode operation. Its Safe Operating Area (SOA) is defined only for pulsed switching conditions. Continuous linear operation would exceed thermal limits due to high power dissipation and lack of SOA derating data, risking thermal runaway.

Does STF20N20 require a gate resistor, and what value is recommended?

Yes-a series gate resistor is mandatory to control dV/dt and suppress ringing. For typical 65–300 kHz flyback designs, a 10–22 Ω non-inductive resistor between driver output and gate pin is recommended. This value balances switching speed (minimizing Q_sw) and EMI suppression while preventing oscillation caused by gate-drain Miller feedback.

How does the TO-220FP package differ electrically from standard TO-220?

TO-220FP features an insulated plastic case with no electrical connection between the metal tab and drain-eliminating need for insulating pads or washers. Electrically, pins 1–3 remain identical, but thermal path is slightly less efficient (R_th(j–c) = 1.2 °C/W vs. 1.0 °C/W for TO-220), trading minor thermal penalty for simplified, safer assembly in grounded-chassis systems.

STF20N20 Specifications

Product attributes: Attribute value

Manufacturer:: STMicroelectronics

Series:: STripFET™ II

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):: 200 V

Current - Continuous Drain (Id) @ 25°C:: 18A (Ta)

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

Rds On (Max) @ Id, Vgs:: 125mOhm @ 10A, 10V

Vgs(th) (Max) @ Id:: 4V @ 250µA

Gate Charge (Qg) (Max) @ Vgs:: 39 nC @ 10 V

Vgs (Max):: ±20V

Input Capacitance (Ciss) (Max) @ Vds:: 940 pF @ 25 V

FET Feature:: -

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

Operating Temperature:: -55°C ~ 150°C (TJ)

Grade:: -

Qualification:: -

Mounting Type:: Through Hole

Supplier Device Package:: TO-220FP

STF20N20 FAQ

1.How can I place an order for STF20N20 through Aetrix?

Please submit a Request for Quotation (RFQ) for STF20N20 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 STF20N20 reliable?

The price and inventory of STF20N20 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for STF20N20 is usually 5 days.

3.What payment methods are accepted for STF20N20?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for STF20N20 transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for STF20N20?

STF20N20 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your STF20N20 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 STF20N20?

For technical support, including STF20N20 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your STF20N20 requirements.

6.How does Aetrix verify that STF20N20 is sourced from the original manufacturer or authorized distributors?

All STF20N20 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 STF20N20 meets industry standards.

7.What is the process for return or replacement of STF20N20?

All STF20N20 units undergo pre-shipment inspection (PSI). If there is an issue with STF20N20, 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 STF20N20 part is unused and in its original packaging.

Return procedure for STF20N20:

1.Submit a request within 90 days.

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

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