In the design of power systems requiring high voltage handling and switching efficiency, selecting the optimal MOSFET involves balancing voltage ratings, conduction losses, and package performance. This analysis uses two established MOSFETs, IRF840ASTRLPBF (high-voltage N-channel) and SIS110DN-T1-GE3 (low-loss N-channel), as benchmarks. It evaluates their domestic alternatives, VBL165R12 and VBQF1104N, comparing key parameters and application suitability to provide a clear selection guide for robust and efficient power switching solutions.
Comparative Analysis: IRF840ASTRLPBF (N-channel) vs. VBL165R12
Analysis of the Original Model (IRF840ASTRLPBF) Core:
This is a 500V N-channel MOSFET from VISHAY in a TO-263 (D2PAK) package. Its design focuses on reliable high-voltage switching with a continuous drain current of 8A and an on-resistance of 850mΩ at 10V gate drive. It serves as a standard choice for medium-power off-line and high-voltage circuits.
Compatibility and Differences of the Domestic Alternative (VBL165R12):
VBsemi's VBL165R12 is a pin-to-pin compatible alternative in the same TO-263 package. Key differences are in electrical parameters: VBL165R12 offers a slightly lower voltage rating (650V vs. 500V) but provides a higher continuous current (12A vs. 8A) and a marginally lower on-resistance (800mΩ@10V vs. 850mΩ@10V).
Key Application Areas:
Original Model IRF840ASTRLPBF: Ideal for applications requiring a proven 500V MOSFET, such as:
Off-line switch-mode power supplies (SMPS).
Motor drives and inverters in industrial controls.
High-voltage power conversion stages.
Alternative Model VBL165R12: Suited for applications needing higher current capability (up to 12A) and a 650V voltage rating, offering an upgrade path in systems like:
Higher-power SMPS and PFC circuits.
Inverters requiring increased current handling.
Comparative Analysis: SIS110DN-T1-GE3 (N-channel) vs. VBQF1104N
This comparison focuses on low on-resistance and fast switching for high-efficiency power conversion.
Analysis of the Original Model (SIS110DN-T1-GE3) Core:
This VISHAY MOSFET is a TrenchFET Gen IV device in an SO-8 package. It is optimized for low RDS(on) and high switching performance, featuring a 100V rating, 5.2A continuous current, and a very low on-resistance of 54mΩ at 10V. Its design targets minimal conduction and switching losses.
Compatibility and Differences of the Domestic Alternative (VBQF1104N):
VBsemi's VBQF1104N, in a DFN8(3x3) package, offers significant performance enhancement. It matches the 100V rating but provides a much higher continuous current (21A vs. 5.2A) and a substantially lower on-resistance (36mΩ@10V vs. 54mΩ@10V).
Key Application Areas:
Original Model SIS110DN-T1-GE3: Excellent for space-constrained, efficiency-critical applications, such as:
Primary-side switching in isolated DC-DC converters.
Synchronous rectification in low-voltage, high-current power supplies.
Power management in computing and telecom.
Alternative Model VBQF1104N: Ideal for next-generation designs demanding higher power density and lower losses, suitable for:
High-current DC-DC converters and POL modules.
Motor drives and battery management systems requiring low RDS(on).
Conclusion:
This analysis outlines two distinct selection paths:
For high-voltage (500V) applications, the original IRF840ASTRLPBF offers proven reliability. Its alternative, VBL165R12, provides a compatible solution with a higher current rating (12A) and a 650V withstand voltage, suitable for upgraded designs.
For high-efficiency, low-voltage (100V) switching, the original SIS110DN-T1-GE3 delivers excellent performance in an SO-8 package. The alternative VBQF1104N significantly outperforms it in current capability (21A) and on-resistance (36mΩ), making it a superior choice for high-power-density applications.
The core principle remains: selection is based on precise requirement matching. Domestic alternatives like VBL165R12 and VBQF1104N provide not only reliable compatibility but also performance enhancements, offering engineers greater flexibility in design optimization and cost management for resilient supply chains.