MOSFET Selection for High-Voltage Power Applications: STW10N95K5, STP28NM50N vs. China Alternatives VBP19R09S and VBM15R30S
In the design of high-voltage and high-efficiency power systems, selecting the right MOSFET is a critical task that balances voltage withstand capability, conduction loss, switching performance, and cost. This article takes two classic high-voltage MOSFETs from STMicroelectronics—STW10N95K5 and STP28NM50N—as benchmarks. It delves into their design cores and application scenarios, while providing a comparative evaluation of two domestic alternative solutions: VBP19R09S and VBM15R30S. By clarifying parameter differences and performance orientations, we aim to offer a clear selection guide for your next high-voltage power design.
Comparative Analysis: STW10N95K5 (N-channel) vs. VBP19R09S
Analysis of the Original Model (STW10N95K5) Core:
This is a 950V N-channel MOSFET from STMicroelectronics, utilizing the TO-247 package. Its design core is to provide robust high-voltage switching capability with integrated Zener protection for enhanced reliability. Key advantages include a high drain-source voltage (Vdss) of 950V, a continuous drain current (Id) of 8A, and a typical on-resistance (RDS(on)) of 0.65Ω (800mΩ @10V per datasheet). It features ST's SuperMESH™ 5 technology, offering a good balance between high voltage rating and switching performance.
Compatibility and Differences of the Domestic Alternative (VBP19R09S):
VBsemi's VBP19R09S is also offered in a TO-247 package and serves as a pin-to-pin compatible alternative. The main differences lie in the electrical parameters: VBP19R09S has a slightly lower voltage rating (900V vs. 950V) but offers a higher continuous current (9A vs. 8A) and a lower on-resistance (750mΩ @10V vs. 800mΩ @10V). It utilizes a SJ_Multi-EPI process.
Key Application Areas:
Original Model STW10N95K5: Ideal for high-voltage applications up to 950V requiring reliable switching and protection, such as:
Switched-Mode Power Supplies (SMPS) for industrial and telecom systems.
Power Factor Correction (PFC) stages.
Motor drives and inverters operating at high bus voltages.
Alternative Model VBP19R09S: Suitable for applications requiring a similar high-voltage threshold (around 900V) but with a need for slightly higher current capability and lower conduction loss. It's a strong candidate for upgrades or new designs in SMPS and PFC circuits where its parameters offer a performance margin.
Comparative Analysis: STP28NM50N (N-channel) vs. VBM15R30S
This comparison focuses on a medium-high voltage MOSFET where the design pursuit is an optimal balance of "voltage rating, current capability, and low on-resistance."
Analysis of the Original Model (STP28NM50N) Core:
The STP28NM50N is a 500V, 21A N-channel MOSFET in a TO-220 package. Its core advantages are:
Solid Voltage and Current Rating: A 500V Vdss and 21A Id make it suitable for a wide range of medium-power off-line applications.
Low Conduction Loss: An on-resistance of 135mΩ @10V (at 10.5A) ensures good efficiency in the on-state.
Proven Package: The TO-220 package offers a good compromise between cost, board space, and thermal performance for many applications.
Compatibility and Differences of the Domestic Alternative (VBM15R30S):
The domestic alternative VBM15R30S represents a "performance-enhanced" choice in the same TO-220 package. It achieves significant improvements in key parameters: the same 500V voltage rating, but a substantially higher continuous current (30A vs. 21A) and a comparable, slightly lower on-resistance (140mΩ @10V vs. 135mΩ @10V). This translates to potentially lower temperature rise and higher efficiency in high-current scenarios.
Key Application Areas:
Original Model STP28NM50N: A versatile workhorse for 500V-class applications requiring good current handling, such as:
Medium-power SMPS and inverters.
Motor drives for appliances and industrial controls.
Uninterruptible Power Supplies (UPS).
Alternative Model VBM15R30S: Better suited for applications demanding higher current capacity within the same 500V range. Its 30A rating and low RDS(on) make it an excellent choice for:
Higher-output-current DC-DC converters or motor drives.
Upgrading existing designs for improved power handling and efficiency.
New designs where component derating is a priority for reliability.
Conclusion
In summary, this analysis reveals two distinct selection pathways for high-voltage applications:
For ultra-high-voltage (near 1000V) applications, the original STW10N95K5, with its 950V rating and integrated protection, remains a reliable choice for demanding industrial and telecom power systems. Its domestic alternative, VBP19R09S, offers a compelling package-compatible option with a slightly adjusted voltage rating (900V) while providing improvements in current (9A) and on-resistance, making it suitable for many upgrade or new design scenarios in this voltage class.
For mainstream 500V-class medium-to-high-power applications, the original STP28NM50N offers a proven balance of voltage, current (21A), and conduction loss. The domestic alternative VBM15R30S provides substantial "performance enhancement," notably a much higher 30A current rating, making it a powerful upgrade path for designs requiring higher power density and increased load capability.
The core takeaway is that selection is not about absolute superiority but about precise requirement matching. In the context of supply chain diversification, domestic alternatives like VBP19R09S and VBM15R30S not only provide viable backup options but also demonstrate competitive or superior performance in specific parameters. This offers engineers greater flexibility and resilience in design trade-offs and cost optimization. A deep understanding of each device's design philosophy and parameter implications is key to unlocking its full potential in your circuit.