MOSFET Selection for High-Voltage Power Applications: STP7N95K3, STW28N60DM2 vs. China Alternatives VBM19R07S and VBP16R20S
In high-voltage power conversion and switching designs, selecting a MOSFET that balances voltage rating, current capability, and conduction losses is critical for reliability and efficiency. This is not a simple drop-in replacement but a careful consideration of performance, ruggedness, cost, and supply chain stability. This article takes two established high-voltage MOSFETs—STP7N95K3 (N-channel) and STW28N60DM2 (N-channel)—as benchmarks, analyzes their design focus and application contexts, and evaluates two domestic alternative solutions, VBM19R07S and VBP16R20S. By clarifying parameter differences and performance orientations, we provide a clear selection guide to help you find the optimal power switching solution in your next high-voltage design.
Comparative Analysis: STP7N95K3 (N-channel) vs. VBM19R07S
Analysis of the Original Model (STP7N95K3) Core:
This is a 950V N-channel MOSFET from STMicroelectronics in a TO-220-3 package. Its design centers on providing robust high-voltage blocking capability in a standard through-hole package. Key strengths are its high drain-source voltage (Vdss) of 950V and a continuous drain current (Id) of 7.2A. The on-resistance (RDS(on)) is 1.35Ω at 10V gate drive, suitable for off-line switching applications where voltage withstand is paramount.
Compatibility and Differences of the Domestic Alternative (VBM19R07S):
VBsemi's VBM19R07S is a direct pin-to-pin compatible alternative in the same TO-220 package. The main differences are in electrical parameters: VBM19R07S offers a slightly lower voltage rating (900V) but features a significantly lower on-resistance of 950mΩ (0.95Ω) at 10V. Its continuous current rating is 7A, closely matching the original. The use of a Super Junction Multi-EPI process aims for good switching performance and efficiency.
Key Application Areas:
Original Model STP7N95K3: Ideal for high-voltage, medium-current switching where 950V rating is essential. Typical applications include:
Off-line switch-mode power supplies (SMPS) like flyback converters.
Power factor correction (PFC) stages.
Lighting ballasts and industrial controls.
Alternative Model VBM19R07S: Suited for applications where 900V rating is sufficient and lower conduction loss is beneficial, such as upgraded or redesigned SMPS and PFC circuits aiming for improved efficiency.
Comparative Analysis: STW28N60DM2 (N-channel) vs. VBP16R20S
This comparison focuses on higher-current, lower on-resistance MOSFETs for demanding power stages.
Analysis of the Original Model (STW28N60DM2) Core:
This STMicroelectronics MOSFET in a TO-247 package is designed for high-power applications. Its core advantages are:
High Current Handling: A continuous drain current of 21A at 600V.
Low Conduction Loss: Features an on-resistance as low as 160mΩ at 10V gate drive, minimizing power dissipation.
Robust Package: The TO-247 package provides excellent thermal performance for high-power dissipation.
Compatibility and Differences of the Domestic Alternative (VBP16R20S):
VBsemi's VBP16R20S is a direct pin-to-pin compatible alternative in the TO-247 package. It matches the original closely in key specs: same 600V voltage rating, same 160mΩ on-resistance at 10V, and a similar continuous current rating of 20A. This makes it a highly equivalent performance replacement.
Key Application Areas:
Original Model STW28N60DM2: Excels in high-efficiency, high-power applications. Typical uses include:
High-power switch-mode power supplies (e.g., server, telecom).
Motor drives and inverters.
UPS and energy conversion systems.
Alternative Model VBP16R20S: Serves as a reliable domestic alternative for the same demanding applications—high-power SMPS, motor drives, and inverters—offering a viable second source with equivalent electrical performance.
Conclusion
In summary, this analysis reveals clear selection and alternative paths for high-voltage applications:
For ultra-high voltage (~950V) medium-current applications, the original STP7N95K3 offers a proven solution with its 950V rating. Its domestic alternative VBM19R07S provides a compelling option with a lower on-resistance (0.95Ω vs. 1.35Ω) at a slightly reduced 900V rating, favoring designs where efficiency gains are prioritized over the maximum voltage margin.
For high-current, low on-resistance applications at 600V, the original STW28N60DM2 sets a strong benchmark with 21A current and 160mΩ RDS(on). The domestic alternative VBP16R20S emerges as a near-identical performance substitute, matching the voltage, on-resistance, and current rating (20A), making it an excellent alternative for supply chain diversification without compromising performance.
The core takeaway is that selection hinges on precise requirement matching. In the context of supply chain diversification, domestic alternatives like VBM19R07S and VBP16R20S not only provide viable backups but also offer performance parity or even advantages in specific parameters, giving engineers greater flexibility and resilience in design trade-offs and cost management. Understanding each device's design intent and parameter implications is key to maximizing its value in the circuit.