MOSFET Selection for Medium-Voltage Power Switching: IRFR9110, IRF820 vs. China Alternatives VBE2103M, VBM165R04
In medium-voltage power switching applications, selecting a MOSFET that balances voltage rating, current capability, and cost is a critical task for engineers. This is not a simple part substitution, but a careful trade-off among performance, reliability, and supply chain stability. This article uses two classic MOSFETs, IRFR9110 (P-channel) and IRF820 (N-channel), as benchmarks, analyzes their design focus and typical applications, and evaluates two domestic alternative solutions, VBE2103M and VBM165R04. By clarifying their parameter differences and performance orientations, we aim to provide a clear selection guide for your next design.
Comparative Analysis: IRFR9110 (P-channel) vs. VBE2103M
Analysis of the Original Model (IRFR9110) Core:
This is a 100V P-channel MOSFET from TI in a DPAK (TO-252AA) package. Its design core is to provide a reliable, cost-effective switching solution for medium-voltage applications. Key advantages include a -100V drain-source voltage rating and a continuous drain current of -3.1A. Its on-resistance (RDS(on)) is 1.2Ω, suitable for various power management and switching functions.
Compatibility and Differences of the Domestic Alternative (VBE2103M):
VBsemi's VBE2103M is also offered in a TO-252 package and serves as a pin-to-pin compatible alternative. The main differences are in electrical parameters: VBE2103M matches the -100V voltage rating but offers significantly improved performance. It features a much lower on-resistance of 220mΩ (at -10V Vgs) and a higher continuous drain current of -10A.
Key Application Areas:
Original Model IRFR9110: Suitable for medium-voltage P-channel switching applications with moderate current requirements, such as power supply polarity protection, load switching in 48-100V systems, or auxiliary power management.
Alternative Model VBE2103M: Ideal for upgrading designs where lower conduction loss and higher current handling are needed. Its low 220mΩ RDS(on) and 10A current rating make it suitable for more efficient power switches, DC-DC converter high-side switches, or motor control circuits within the same voltage range.
Comparative Analysis: IRF820 (N-channel) vs. VBM165R04
This N-channel comparison focuses on high-voltage switching capability and ruggedness.
Analysis of the Original Model (IRF820) Core:
The IRF820 from TI is a classic 500V N-channel MOSFET in a TO-220AB package. Its core advantage is a high voltage rating (500V Vdss) suitable for off-line and high-voltage switching. It offers a continuous drain current of 2.5A with an on-resistance of 3Ω (at 10V Vgs), providing a robust solution for various high-voltage, low-to-medium current applications.
Compatibility and Differences of the Domestic Alternative (VBM165R04):
VBsemi's VBM165R04, in a TO-220 package, is a direct compatible alternative with enhanced voltage specs. It features a higher 650V drain-source voltage rating. While its on-resistance is 2200mΩ (2.2Ω at 10V Vgs), comparable to the original, it offers a slightly higher continuous current rating of 4A.
Key Application Areas:
Original Model IRF820: A reliable choice for classic high-voltage switching applications like offline SMPS (e.g., flyback converter power switches), electronic ballasts, or induction heating where 500V rating and 2.5A current are sufficient.
Alternative Model VBM165R04: Better suited for applications requiring a higher voltage safety margin up to 650V, such as industrial SMPS, power factor correction (PFC) stages, or motor drives where the increased 4A current capability provides extra headroom.
Conclusion:
This analysis reveals two distinct selection paths:
For P-channel applications around 100V, the original IRFR9110 provides a proven, standard solution. Its domestic alternative VBE2103M offers a significant performance upgrade with much lower on-resistance (220mΩ vs. 1.2Ω) and higher current (10A vs. 3.1A), making it an excellent choice for efficiency-focused redesigns or new projects.
For N-channel applications requiring high voltage blocking, the classic IRF820 (500V) is a reliable workhorse. Its alternative VBM165R04 provides a higher voltage rating (650V) and slightly higher current (4A vs. 2.5A), offering enhanced robustness for more demanding high-voltage environments.
The core conclusion is that selection depends on precise requirement matching. In the context of supply chain diversification, domestic alternatives like VBE2103M and VBM165R04 not only provide reliable backup options but also offer performance enhancements or superior specs in key areas, giving engineers greater flexibility in design and cost optimization. Understanding each device's parameter implications is key to maximizing its value in the circuit.