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STMicroelectronics STW20NB50
- Part No.:
- STW20NB50
- Manufacturer:
- STMicroelectronics
- Category:
- FETs, MOSFETs
- Package:
- TO-247-3
- Datasheet:
-
STW20NB50.pdf
- Description:
- MOSFET N-CH 500V 20A TO247-3
- Quantity:
- Payment:
- Shipping:
Inventory:5,472
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Product details
Overview
STW20NB50 from STMicroelectronics is an N-channel enhancement-mode PowerMESH™ MOSFET rated for 500 V drain-source voltage, 20 A continuous drain current at 25 °C, and 0.22 Ω typical RDS(on) at VGS = 10 V. It features ±30 V gate-source voltage rating, 100% avalanche tested, and optimized for high-speed switching in high-current power conversion stages.
For engineers reviewing the STW20NB50 datasheet, STW20NB50 pinout, STW20NB50 application, or STW20NB50 equivalent, key selection criteria include its 4 V/ns dv/dt capability, 85 nC total gate charge, 3600 pF input capacitance, repetitive avalanche rating (20 A), and TO-247 thermal resistance of 0.5 °C/W junction-to-case.
Technical Context
This MOSFET employs ST's proprietary PowerMESH™ strip layout and edge termination to achieve low RDS(on) per die area and exceptional ruggedness. Its unclamped inductive switching performance is validated up to 20 A repetitive avalanche current with 1000 mJ single-pulse energy at Tj = 25 °C.
The device delivers fast switching with 32 ns turn-on delay and 15 ns rise time under 400 V/20 A conditions (RG = 4.7 Ω), supported by minimized gate charge (Qg = 85 nC typ.) and low intrinsic capacitances (Ciss = 3600 pF, Coss = 460 pF).
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VDSS | 500 V - supports primary-side switching in offline SMPS up to 400 V DC bus with margin |
| RDS(on) max | 0.25 Ω - limits conduction loss to ≤5 W at 20 A DC, enabling compact heatsink design |
| ID cont @ Tc=100°C | 12.7 A - defines usable current derating in thermally constrained industrial enclosures |
| Qg | 85 nC - determines gate driver power requirement (~0.85 mW per MHz at 10 V swing) |
| dv/dt capability | 4 V/ns - ensures immunity to false triggering during fast transient recovery in bridge topologies |
| EAS | 1000 mJ - enables robust operation under unclamped inductive load faults without snubber |
| Rthj-case | 0.5 °C/W - allows 250 W dissipation at ΔT = 125 °C, critical for forced-air-cooled welder inverters |
Pinout & Package
Delivered in TO-247 package with isolated tab (drain-connected). Package dimensions conform to JEDEC TO-247 standard (L = 20.0 mm, H = 15.6 mm, D = 2.4 mm), rated for 300 °C lead temperature during soldering.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Drain (Tab) | Main high-side current path | Electrically connected to metal tab; requires insulated mounting in floating applications |
| Source | Reference node for gate drive and current sensing | Low-inductance connection point for shunt resistor placement and gate return path |
| Gate | Control terminal for channel modulation | High-impedance input requiring <4.7 Ω series resistance to damp ringing during fast transitions |
Key Features
| Feature | Design Value |
|---|---|
| PowerMESH™ cell architecture | Reduces RDS(on) by 22% vs. conventional planar MOSFETs of same die area |
| 100% unclamped inductive avalanche tested | Guarantees operation under worst-case hard-switching fault without parameter shift |
| Low Ciss/Coss ratio (7.8:1) | Improves zero-voltage switching (ZVS) soft-start reliability in resonant converters |
| ±30 V gate rating | Supports gate drive with 15 V logic-level controllers plus 10 V noise margin |
| 150 °C max junction temperature | Enables operation in sealed industrial enclosures without active cooling |
Applications
| Welding Inverter Primary Switch | UPS DC-AC Inverter Stage |
|---|---|
Use Scenario: High-frequency (20–50 kHz) hard-switched full-bridge inverter converting 400 V DC bus to 50/60 Hz AC output for arc stability. IC Role / Device Role / Timing Role: Main switching device handling 20 A peak load current with repetitive 1000 mJ avalanche energy absorption during short-circuit events. Use Value: 0.22 Ω RDS(on) reduces conduction losses by 35% vs. legacy 0.35 Ω devices, improving thermal headroom in compact chassis. | Use Scenario: Online double-conversion UPS delivering clean sine-wave output during grid failure, operating continuously at 85% load. IC Role / Device Role / Timing Role: High-side switch in IGBT/MOSFET hybrid inverter leg, managing 400 V DC link with 4 V/ns dv/dt immunity during transformer saturation transients. Use Value: 4 V/ns dv/dt rating prevents spurious turn-on during fast diode recovery, eliminating need for negative gate bias circuitry. |
| Industrial Motor Drive Output Stage | High-Voltage SMPS Primary Switch |
Use Scenario: 3 kW variable-frequency drive powering induction motors in HVAC compressors, requiring >100,000-hour field reliability. IC Role / Device Role / Timing Role: Phase-leg switch subjected to 12.7 A continuous current at 100 °C case temperature, with repetitive avalanche stress during regenerative braking. Use Value: 12.7 A rating at 100 °C enables direct replacement of larger TO-3P devices, reducing PCB footprint by 40%. | Use Scenario: 1.5 kW flyback or LLC resonant converter for medical equipment power supply, requiring low EMI and high efficiency. IC Role / Device Role / Timing Role: Primary-side switch operating at 100 kHz with 85 nC gate charge, minimizing driver losses and enabling use of low-cost bipolar gate drivers. Use Value: 85 nC Qg reduces gate drive power by 28% vs. comparable 120 nC MOSFETs, lowering driver IC thermal stress. |
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 |
|---|---|---|---|
| STW20NK50Z | 500 V, 0.20 Ω RDS(on), 20 A, Zener-protected gate, higher Ciss (4200 pF) | Better gate robustness but slower switching due to +17% input capacitance | Preferred where ESD immunity outweighs switching speed requirements |
| IXFH20N50P | 500 V, 0.24 Ω RDS(on), 20 A, 100% UIS tested, lower Qg (72 nC) | Lower gate charge improves efficiency in high-frequency designs but reduced avalanche energy (750 mJ) | Optimal for >200 kHz SMPS where conduction loss dominates over fault robustness |
Compared with STW20NK50Z and IXFH20N50P, the STW20NB50 offers the best balance of avalanche ruggedness (1000 mJ), moderate gate charge (85 nC), and proven field reliability in welding and UPS systems-making it preferred for mission-critical industrial inverters where fault tolerance is non-negotiable.
Availability
STW20NB50 is available at Aetrix Electronics and suitable for welding inverters, uninterruptible power supplies, industrial motor drives, and high-voltage switch-mode power supplies requiring stable component supply across multi-year production cycles.
Supply support for STW20NB50 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 analog, MCU, power, and sensor solutions for industrial, automotive, and consumer markets.
The STW20NB50 belongs to ST's PowerMESH™ HV MOSFET product line, engineered specifically for rugged high-voltage switching in industrial power conversion where avalanche capability and thermal stability are critical.
FAQ
What is the maximum safe operating temperature for STW20NB50?
The STW20NB50 has a maximum junction temperature of 150 °C and a storage temperature range of –65 to +150 °C. Its thermal resistance junction-to-case is 0.5 °C/W, meaning at 250 W dissipation, the case must be held at ≤25 °C to avoid exceeding Tj max. Derating begins at 2 W/°C above 25 °C case temperature.
Does STW20NB50 require a gate resistor, and what value is recommended?
Yes-a gate resistor is required to control dV/dt and suppress oscillation. For hard-switching at 20 A with 4.7 Ω gate resistance (per datasheet test condition), turn-on delay is 32 ns and rise time is 15 ns. Lower values (≤2.2 Ω) increase switching speed but risk ringing; higher values (>10 Ω) reduce EMI but raise switching losses.
Can STW20NB50 replace STW20NK50 in existing designs?
Yes, with verification of gate drive strength and layout parasitics. The STW20NB50 has identical pinout and voltage/current ratings but lacks integrated gate Zener protection. External 18 V gate clamp diodes are recommended if the original design relied on the NK50's built-in protection against overvoltage transients.
Is STW20NB50 suitable for synchronous rectification?
No-it is not optimized for synchronous rectification. Its body diode has 1.6 V forward voltage and 700 ns reverse recovery time, resulting in high conduction and switching losses in low-voltage secondary-side applications. Dedicated low-Qrr, low-VF MOSFETs like STP16NF06L are recommended instead.
STW20NB50 Specifications
- Product attributes
- Attribute value
- Manufacturer:
- STMicroelectronics
- Series:
- PowerMESH™
- Package/Case:
- TO-247-3
- 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:
- 20A (Tc)
- Drive Voltage (Max Rds On, Min Rds On):
- 10V
- Rds On (Max) @ Id, Vgs:
- 250mOhm @ 10A, 10V
- Vgs(th) (Max) @ Id:
- 5V @ 250µA
- Gate Charge (Qg) (Max) @ Vgs:
- 110 nC @ 10 V
- Vgs (Max):
- ±30V
- Input Capacitance (Ciss) (Max) @ Vds:
- 4700 pF @ 25 V
- FET Feature:
- -
- Power Dissipation (Max):
- 250W (Tc)
- Operating Temperature:
- 150°C (TJ)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Through Hole
- Supplier Device Package:
- TO-247-3
STW20NB50 FAQ
1.How can I place an order for STW20NB50 through Aetrix?
Please submit a Request for Quotation (RFQ) for STW20NB50 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 STW20NB50 reliable?
The price and inventory of STW20NB50 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for STW20NB50 is usually 5 days.
3.What payment methods are accepted for STW20NB50?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for STW20NB50 transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for STW20NB50?
STW20NB50 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your STW20NB50 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 STW20NB50?
For technical support, including STW20NB50 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your STW20NB50 requirements.
6.How does Aetrix verify that STW20NB50 is sourced from the original manufacturer or authorized distributors?
All STW20NB50 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 STW20NB50 meets industry standards.
7.What is the process for return or replacement of STW20NB50?
All STW20NB50 units undergo pre-shipment inspection (PSI). If there is an issue with STW20NB50, 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 STW20NB50 part is unused and in its original packaging.
Return procedure for STW20NB50:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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