STP20NF20L - 200V 18A N-Ch STripFET MOSFET | STMicroelectronics
MPN: STP20NF20L ✓ Active| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $0.83 | $0.83 |
| 10 | $0.78 | $7.80 |
| 100 | $0.65 | $65.00 |
| 500 | $0.55 | $275.00 |
| 1,000 | $0.48 | $480.00 |
STP20NF20L Overview
What is a Power MOSFET? A power MOSFET (Metal-Oxide-Semiconductor Field-Effect Transistor) is a voltage-driven semiconductor switch used to control high currents and voltages in power-conversion circuits. Power MOSFETs sit at the heart of switching power supplies (SMPS), motor drives, and DC-DC converters, where they repeatedly switch between a low-resistance ON state and a high-resistance OFF state. The "N-channel" designation indicates that current flows when a positive gate-source voltage is applied, which is naturally compatible with standard gate-drive ICs and yields lower on-resistance per unit silicon area than equivalent P-channel devices.
Key features of the STP20NF20L include a drain-source voltage (VDS) of 200 V, continuous drain current (ID) of 18 A at TC, maximum on-resistance (RDS(on)) of 0.10 Ω, and low gate charge for high-efficiency switching. The TO-220 through-hole package provides 110 W power dissipation at TC with excellent thermal conductivity when bolted to a heatsink.
Architecturally, the STripFET™ process is a planar/standard-cell silicon-gate technology that achieves low specific on-resistance (RDS(on) × area) by minimizing the contribution of the epi-layer resistance. This translates directly into lower conduction losses and cooler operation in continuous-current applications such as synchronous rectifiers and high-side switches.
Typical applications include isolated DC-DC converters (primary-side switch), uninterruptible power supplies (UPS), low-voltage motor control, solenoid drivers, and audio amplifiers. The low gate charge also enables direct interfacing with low-power PWM controllers.
When using this device, ensure the gate-drive voltage fully enhances the channel (typically 10 V) and that VDS transients are clamped below the 200 V rating. Proper heatsink mounting is essential because the TO-220 package relies on the bolted tab to dissipate the bulk of its 110 W rating.
This page synthesizes distributor pricing, parametric drop-in alternatives, and practical design notes not found in the manufacturer datasheet alone, optimized for engineers evaluating the STP20NF20L.
Drop-in alternatives for STP20NF20L — same package, pin-to-pin compatible. Different-package parts requiring PCB rework are excluded.
Variants in this series
Same-series models that are drop-in compatible with STP20NF20L (same form factor and footprint) — differing in Lead-Free, Package, Technology.
Quick Comparison Tool — Select alternative parts for side-by-side comparison:
STP20NF20
✅ Drop-In📋 Reference alternative (not in catalog)
STF20NF20L
✅ Drop-In📋 Reference alternative (not in catalog)
STD20NF20L
✅ Drop-In📋 Reference alternative (not in catalog)
IRF640NPBF
✅ Drop-In✓ In Stock
$0.88 / Unit
View Datasheet →IRFB17N20D
✅ Drop-In📋 Reference alternative (not in catalog)
STP20NF20L Maximum Ratings & Electrical Characteristics
| FET Type | N-Channel |
| Technology | STripFET™ (planar silicon gate) |
| Drain-Source Voltage (VDS) | 200 V |
| Continuous Drain Current (ID) | 18 A (Tc) |
| On-Resistance (RDS(on)) | 0.10 Ω (max) |
| Power Dissipation (PD) | 110 W (Tc) |
| Gate Charge (Qg) | Low gate charge (STripFET™ optimized) |
| Input Capacitance (Ciss) | Minimized by STripFET™ process |
| Package | TO-220 (through-hole, 3-lead) |
| Mounting Type | Through Hole |
| RoHS Status | Compliant |
| Lead-Free | Yes |
| Process Technology | STripFET™ (low Qg, low Ciss) |
STP20NF20L Pin Configuration
| Pin 1 | Gate — MOSFET gate input — logic-level threshold |
| Pin 2 | Drain — MOSFET drain (also electrically tied to metal tab) |
| Pin 3 | Source — MOSFET source |
Safe Operating Area (DC)
Typical Applications
STP20NF20L is suitable for 6 applications: Isolated DC-DC Converter Primary Switch, Uninterruptible Power Supply (UPS) Battery Switch, Low-Voltage DC Motor Drive (H-Bridge Leg), Solenoid and Relay Driver, Audio Amplifier Output Switch (Class-D), Solar Inverter Low-Side Switch.
Isolated DC-DC Converter Primary Switch
The STP20NF20L serves as the primary-side high-voltage switch in flyback and forward isolated DC-DC converters up to ~150 W. Its 200 V VDS rating covers rectified 100-127 V AC bus rails with safe margin, while the logic-level gate drive enables direct interfacing with low-voltage PWM controllers (UCC28C42, UC3842 families) without bootstrap gate-drive complexity. The 0.10 Ω RDS(on) keeps conduction losses under 30 W at 18 A peak primary current, and the STripFET™ low gate charge (~30 nC typical) limits switching loss at 50-200 kHz operation. Placed between the rectified bus and the primary winding of the transformer with an RCD snubber across drain-source, this part achieves 90%+ efficiency in typical 100 W telecom and industrial isolated brick converters.
Recommended
Uninterruptible Power Supply (UPS) Battery Switch
In line-interactive and online UPS systems, the STP20NF20L functions as a low-side battery disconnect switch or inverter leg switch at 48 V battery bus rails. The 200 V rating provides substantial margin above typical 48 V (60 V max) battery voltages, while 18 A continuous rating supports 1 kW inverter legs (24 V × 18 A = 432 W per switch). The logic-level gate drive allows direct MCU control of battery isolation without gate-drive transformers. With low RDS(on) of 0.10 Ω, conduction loss at 18 A is ~32 W, manageable with a modest TO-220 clip-on heatsink. This application particularly benefits from the part's avalanche ruggedness during inductive kickback from the inverter output filter.
Recommended
Low-Voltage DC Motor Drive (H-Bridge Leg)
The STP20NF20L operates as a high-side or low-side switch in 24-48 V brushed DC motor H-bridge drives up to ~1 HP. Its 200 V VDS rating provides ample margin above 48 V bus transients from back-EMF and regenerative braking, while the 18 A continuous current supports motor currents up to 15 A continuous per leg with proper heatsinking. The logic-level gate threshold allows direct 3.3 V or 5 V MCU PWM drive, eliminating the need for gate-driver ICs in cost-sensitive applications. With low gate charge and fast switching edges, PWM frequencies up to 50 kHz are achievable for smooth torque control. The TO-220 package with bolted tab provides robust mechanical mounting in vibration-prone motor control environments.
Recommended
Solenoid and Relay Driver
Industrial solenoid and relay drivers benefit from the STP20NF20L's 200 V rating for switching 110-220 V rectified DC loads. The 18 A continuous current handles high-inrush solenoid coils, while the low RDS(on) minimizes steady-state power dissipation in continuous-duty applications. Logic-level gate drive simplifies interface with 24 V PLC outputs and 5 V logic controllers. The avalanche energy rating of the STripFET™ die provides robustness against the inductive kickback when de-energizing the solenoid coil — a common failure mode for undersized MOSFETs. Used in pneumatic valve banks, HVAC damper actuators, and industrial automation relay replacement.
Recommended
Audio Amplifier Output Switch (Class-D)
In Class-D audio amplifiers operating from ±50-100 V rails, the STP20NF20L serves as a high-current output switch for subwoofer and professional audio channels. The 200 V rating covers the 2× supply voltage stress typical of bridge-tied load (BTL) Class-D topologies, while the 18 A peak current supports 200 W into 4 Ω loads. Low gate charge minimizes crossover distortion by enabling high PWM carrier frequencies (250-500 kHz). The TO-220 through-hole package provides excellent thermal dissipation for sustained audio power levels. Note that the part's switching speed should be evaluated against EMI requirements for the target audio band.
Recommended
Solar Inverter Low-Side Switch
In small-scale photovoltaic inverter designs, the STP20NF20L functions as a low-side switch in the buck-stage converting 24-48 V solar panel strings to battery or grid-tie bus voltages. The 200 V VDS rating handles open-circuit panel voltages up to 150 V (typical 36-cell strings in series), while the logic-level gate enables direct interface with solar charge controller ICs. The 0.10 Ω RDS(on) maximizes conversion efficiency — critical for energy-harvesting applications where every percentage point matters. With proper heatsinking, the part handles continuous 18 A for solar charge controllers in the 800 W peak power range. Its avalanche ruggedness provides protection against the inductive transients common in solar installations.
Recommended
Recommended Products Summary
Engineering reference data for STP20NF20L — comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | STP20NF20 | STF20NF20L | STD20NF20L | IRF640N | IRFB17N20D |
|---|---|---|---|---|---|---|
| Brand | STMicroelectronics | STMicroelectronics | STMicroelectronics | STMicroelectronics | Infineon | Infineon |
| Package | TO-220 | TO-220 - same | TO-220FP - same footprint, isolated tab | DPAK - surface-mount | TO-220 - same | TO-220AB - same |
| Drain-Source Voltage (VDS) | 200 V | 200 V | 200 V | 200 V | 200 V | 200 V |
| Continuous Drain Current (ID) | 18 A (Tc) | 18 A | 18 A | 18 A | 18 A | 17 A |
| On-Resistance (RDS(on)) | 0.10 Ω | 0.10 Ω | 0.10 Ω | 0.10 Ω | 0.18 Ω (+80%) | 0.17 Ω (+70%) |
| Gate Threshold Type | Logic-level (5V drive) | Standard (10V drive) | Logic-level (5V drive) | Logic-level (5V drive) | Standard (10V drive) | Standard (10V drive) |
| Power Dissipation (PD) | 110 W (Tc) | 110 W | 30 W (TO-220FP isolated) | 100 W (DPAK) | 125 W | 70 W |
| Process Technology | STripFET™ | STripFET™ | STripFET™ | STripFET™ | HEXFET™ (similar planar) | HEXFET™ |
| Unit Price (qty 100, USD) | $0.65 | $0.60 | $0.70 | $0.55 | $0.75 | $0.85 |
Key Differentiators
- Logic-level gate threshold with 200V/18A/0.10Ω ratings (vs IRF640N)
- Lowest RDS(on) in TO-220 200V/18A class (vs IRFB17N20D)
- STripFET™ process provides low gate charge (vs IRF640N)
Design Notes
Estimated: At ID = 18 A and RDS(on) = 0.10 Ω, conduction loss P = I² × R = 18² × 0.10 = 32.4 W. The TO-220 package has θJC of ~1.0 °C/W; with TC maintained at 100 °C, junction-to-case rise is 32.4 °C, leaving only ~47 °C margin to the 150 °C TJ max. A heatsink with θSA ≤ 1.5 °C/W is mandatory for continuous 18 A operation. For intermittent loads (motor drives), thermal mass in the tab itself allows short bursts beyond continuous rating.
Keep the high-current switching loop (drain-source to bulk cap to transformer primary) as small as physically possible — ideally <2 cm² of loop area. Excessive loop inductance causes VDS ringing that can exceed the 200 V rating during turn-off. Place a snubber capacitor (1-10 nF ceramic + 10-100 Ω resistor) directly across drain-source if the ringing exceeds 70% of VDS. Gate-drive traces should be kept away from drain traces to avoid dv/dt dV/dt-induced gate-source overvoltage.
Do NOT use the STP20NF20L without verifying gate-source voltage. Even though it is logic-level, applying VGS below 4.5 V will leave the MOSFET in the linear region, dissipating enormous power and likely destroying the die. For 3.3 V logic systems, add a gate-driver stage (single MOSFET or dedicated driver) to ensure VGS reaches 10 V. Also: never exceed VGS = ±20 V maximum rating — gate-oxide failure is permanent and silent.
Through-hole TO-220 mounting requires the metal tab to be bolted flat against a heatsink or copper pour with thermal compound. Tab-to-heatsink thermal resistance should be ≤ 0.5 °C/W; ensure mounting torque is 0.6-0.8 N·m to avoid bowing. The three leads should be bent only once if needed, and strain-relieved if used in vibration environments. Maintain ≥5 mm clearance between the tab and adjacent PCB traces rated above 100 V.
Compliance Information
RoHS and REACH compliant per ST product page; not AEC-Q100 qualified (industrial/consumer part, not automotive grade). Halogen-free status not explicitly stated in the verified web data.
