In modern power design, selecting the optimal MOSFET involves balancing performance, size, cost, and supply chain stability. This article takes two representative MOSFETs—FDMC7692S (low-voltage N-channel) and FQP6N90C (high-voltage N-channel)—as benchmarks, analyzes their design focus and application scenarios, and evaluates two domestic alternative solutions: VBQF1310 and VBM19R05S. By comparing parameter differences and performance orientations, we provide a clear selection guide to help you find the most suitable power switching solution for your next design.
Comparative Analysis: FDMC7692S (N-channel) vs. VBQF1310
Analysis of the Original Model (FDMC7692S) Core:
This is a 30V N-channel MOSFET from onsemi, in a compact MLP (3.3x3.3) package. Its design core is to minimize conduction loss using advanced PowerTrench technology. Key advantages include: a low on-resistance of 9.3mΩ at 10V gate drive, and a continuous drain current rating of 18A. It is specifically optimized for power and load switching applications in laptops and portable battery packs.
Compatibility and Differences of the Domestic Alternative (VBQF1310):
VBsemi’s VBQF1310 is offered in a DFN8 (3x3) package and serves as a functional alternative. The main differences are in electrical parameters: VBQF1310 has a higher continuous current rating (30A) and a lower on-resistance of 13mΩ at 10V, but its threshold voltage and gate charge characteristics may differ.
Key Application Areas:
- Original Model FDMC7692S: Ideal for space-constrained, efficiency-critical load switching in 12V–30V systems, such as:
- Power switches in laptops, tablets, and portable devices.
- Load management and battery protection circuits.
- Compact DC-DC converters and POL (point-of-load) modules.
- Alternative Model VBQF1310: Suitable for applications requiring higher current capability (up to 30A) and lower conduction loss, while maintaining a small footprint. Useful in upgraded power switches, motor drives, or higher-current DC-DC stages.
Comparative Analysis: FQP6N90C (N-channel) vs. VBM19R05S
This comparison shifts to high-voltage switching, where breakdown voltage and ruggedness are critical.
Analysis of the Original Model (FQP6N90C) Core:
This is a 900V N-channel MOSFET from onsemi in a TO-220 package. It is designed for high-voltage, medium-current applications. Key features include: a drain-source voltage of 900V, continuous current of 6A, and an on-resistance of 2.3Ω at 10V gate drive and 3A drain current. It offers robust performance in offline power supplies and industrial controls.
Compatibility and Differences of the Domestic Alternative (VBM19R05S):
VBsemi’s VBM19R05S is also in a TO-220 package and provides a direct pin-to-pin alternative. Its parameters show a similar voltage rating (900V) but a slightly lower continuous current (5A) and a significantly lower on-resistance of 1500mΩ (1.5Ω) at 10V. It uses SJ_Multi-EPI technology for improved efficiency.
Key Application Areas:
- Original Model FQP6N90C: Best suited for high-voltage, medium-power applications such as:
- Offline switch-mode power supplies (SMPS).
- Power factor correction (PFC) stages.
- Industrial motor drives and inverter circuits.
- Alternative Model VBM19R05S: Offers enhanced conduction performance with lower on-resistance, making it suitable for high-efficiency revisions of SMPS, lighting ballasts, and other 900V systems where reduced loss is prioritized.
Conclusion
This analysis reveals two distinct selection paths:
For low-voltage, high-current switching in compact designs, the original FDMC7692S provides an excellent balance of low RDS(on) (9.3mΩ) and 18A current capability in a small MLP package, making it ideal for portable electronics power management. Its domestic alternative VBQF1310 offers higher current (30A) and lower on-resistance (13mΩ), serving as a performance-enhanced option for upgrades requiring higher power density.
For high-voltage applications, the original FQP6N90C delivers reliable 900V/6A performance in a robust TO-220 package, suited for industrial and offline power systems. The domestic alternative VBM19R05S matches the voltage rating while offering lower on-resistance (1.5Ω), providing an efficient alternative for designs focusing on reduced conduction losses.
The core insight is that selection depends on precise requirement matching. Domestic alternatives not only supply chain resilience but also offer parameter advancements, giving engineers greater flexibility in design trade-offs and cost optimization. Understanding each device’s design philosophy and parametric implications is key to maximizing circuit performance.