With the rapid advancement of urban air mobility (UAM), AI-piloted inter-city eVTOL aircraft for integrated cargo and passenger transport represent the future of high-efficiency logistics and transportation. The propulsion, power management, and auxiliary systems, serving as the "heart and muscles" of the aircraft, demand extreme reliability, high power density, and superior efficiency. The selection of power MOSFETs is critical, directly determining the performance, safety, weight, and operational range of the entire powertrain. Addressing the stringent requirements of eVTOLs for ultra-high reliability, peak efficiency, lightweight design, and harsh environment operation, this article develops a practical and optimized MOSFET selection strategy focused on scenario-based adaptation.
I. Core Selection Principles and Scenario Adaptation Logic
(A) Core Selection Principles: Multi-Dimensional Extreme Requirements
MOSFET selection for aerospace-grade applications requires coordinated adaptation across voltage, loss, package, and reliability under extreme conditions:
Extreme Voltage & Safety Margin: For high-voltage propulsion buses (e.g., 800V DC), select devices with sufficient voltage rating (≥650V) and a safety margin >20% to withstand transients and regenerative braking spikes. For lower-voltage auxiliary buses (28V/270V), margin should be ≥50%.
Ultra-Low Loss for Maximum Efficiency: Prioritize devices with minimal Rds(on) and optimized switching figures (Qg, Coss) to minimize conduction and switching losses. This is paramount for extending flight time, reducing thermal load, and maximizing power density.
Package for Power Density & Reliability: Choose packages with excellent thermal performance (low RthJC) and proven reliability under vibration and thermal cycling (e.g., TO-247, TO-263). Balance power handling capability against weight and volume.
Aerospace-Grade Reliability: Devices must operate reliably across a wide temperature range (-55°C to 175°C+), possess high robustness against avalanche events, and exhibit stable performance under mechanical stress and altitude variations.
(B) Scenario Adaptation Logic: Categorization by Critical Function
Divide the electrical system into three core scenarios: First, High-Voltage Propulsion Motor Drive (flight-critical), requiring ultra-efficient, high-power switching. Second, Battery Management & High-Voltage Safety Isolation (safety-critical), requiring robust high-voltage switching for contactors and load disconnect. Third, Auxiliary Power & Actuation Systems (mission-critical), requiring high-current handling in compact formats for DC-DC converters, servo drives, and environmental control.
II. Detailed MOSFET Selection Scheme by Scenario
(A) Scenario 1: High-Voltage Propulsion Motor Inverter (50kW-500kW per motor) – Flight-Critical Power Device
eVTOL propulsion motors require extremely efficient, fast-switching MOSFETs in a multi-phase inverter configuration to handle high continuous and peak currents at high DC bus voltages.
Recommended Model: VBM165R15S (Single-N, 650V, 15A, TO-220, SJ_Multi-EPI)
Parameter Advantages: Super-Junction (SJ_Multi-EPI) technology achieves an excellent balance of high voltage (650V) and low specific on-resistance (Rds(on) of 220mΩ at 10V). The 15A rating is suitable for parallel use in multi-phase bridge legs. The TO-220 package offers a robust thermal path and is compatible with high-reliability mounting.
Adaptation Value: Enables high-efficiency inverter design for 800V DC bus systems. The low Rds(on) minimizes conduction losses in each switch, directly contributing to longer flight endurance. The SJ technology allows for higher switching frequencies, reducing magnetic component size and weight in the motor drive.
Selection Notes: Requires extensive paralleling for high-power motor phases. Careful attention to dynamic current sharing (gate drive symmetry, layout) is essential. Must be paired with high-performance, reinforced isolation gate driver ICs. Requires derating based on junction temperature and switching frequency.
(B) Scenario 2: Battery System & High-Voltage Safety Isolation – Safety-Critical Isolation Device
The battery pack contactors and high-voltage auxiliary load disconnect circuits require reliable high-side switches capable of safely isolating faults and handling high voltage with minimal leakage.
Recommended Model: VBP2205N (Single-P, -200V, -55A, TO-247, Trench)
Parameter Advantages: High voltage rating (-200V) is suitable for 270V high-voltage DC auxiliary buses or as a safety switch in sections of a serial battery string. Very low Rds(on) (50mΩ at 10V) minimizes voltage drop and power loss during conduction. High current rating (-55A) and the robust TO-247 package ensure reliable operation under load.
Adaptation Value: Provides a robust and efficient solution for high-side switching in HV circuits. Its P-channel configuration simplifies high-side drive in non-isolated sections. Enables rapid fault isolation in battery management units (BMU) or power distribution units (PDU), enhancing overall system safety.
Selection Notes: Verify application voltage and required isolation level. Gate drive requires appropriate level translation. The -3.5V Vth requires sufficient gate drive voltage margin. Implement overtemperature and overcurrent sensing on the load side.
(C) Scenario 3: Auxiliary Power Conversion & High-Current Actuation – Mission-Critical Support Device
Auxiliary systems like high-power 28V DC-DC converters, servo pumps, and landing gear actuators require MOSFETs that offer an exceptional current-density-to-size ratio and very low conduction loss.
Recommended Model: VBNC1303 (Single-N, 30V, 98A, TO-262, Trench)
Parameter Advantages: Extremely low Rds(on) of 2.4mΩ at 10V, combined with a very high continuous current rating of 98A. The TO-262 (D²PAK) package offers an excellent footprint for its current-handling capability, favoring power density. Low Vth (2V) ensures compatibility with standard logic-level drives.
Adaptation Value: Ideal for synchronous rectification in high-current 28V DC-DC converters, significantly boosting efficiency. Also perfectly suited as the main switch in electro-mechanical actuator (EMA) drivers or hydraulic pump motor controllers, where low voltage drop is critical for performance and thermal management.
Selection Notes: Ensure the 30V rating provides sufficient margin for the application bus (e.g., 28V). The very high di/dt capability demands careful PCB layout to minimize parasitic inductance in the power loop. Requires a dedicated gate driver with strong sink/source capability.
III. System-Level Design Implementation Points
(A) Drive Circuit Design: Matched to Aerospace Demands
VBM165R15S: Must be driven by high-performance, reinforced isolated gate drivers (e.g., Si8239x) with negative turn-off capability for noise immunity. Implement active Miller clamp protection.
VBP2205N: Can use a simple level-shifting circuit or a dedicated high-side driver. Include a strong pull-up resistor to ensure robust turn-off.
VBNC1303: Use a low-side driver with high peak current (≥2A) to charge/discharge the gate rapidly. A small gate resistor (1-5Ω) is recommended to control switching speed and mitigate ringing.
(B) Thermal Management & Mechanical Design: Extreme Environment Adaptation
General: All devices must be mounted on heatsinks with aerospace-grade thermal interface materials. Thermal analysis must account for high-altitude, reduced-convection conditions.
VBM165R15S/VBP2205N: Mount on liquid-cooled cold plates or high-performance finned heatsinks. Use thermal vias and thick copper on PCB.
VBNC1303: Ensure the metal tab is properly soldered or clamped to a heatsink. The PCB copper pour must be extensive (>500mm²).
Vibration: Secure all MOSFETs and heatsinks with appropriate locking mechanisms (lock washers, thread locker) to withstand high vibration levels.
(C) EMC, Protection & Reliability Assurance
EMI Suppression: Implement snubber networks (RC across drain-source) for high-voltage switches (VBM165R15S). Use ferrite beads on gate drives. Ensure excellent shielding and grounding of inverter stages.
Protection Circuits:
Overcurrent: Precision shunt resistors or isolated current sensors in each phase/load path, feeding into fast comparators or ADCs in the controller.
Overtemperature: NTC thermistors or digital temperature sensors (e.g., TMP125) embedded in heatsinks near critical MOSFETs.
Voltage Transients: Use Avalanche-rated MOSFETs (UIS rating). Place TVS diodes (e.g., SMCJ series) at battery terminals, motor phases, and DC-link capacitors. Implement varistors for high-energy surges.
Redundancy: Critical circuits (e.g., safety isolation with VBP2205N) should have redundant sensing paths or backup switches.
IV. Scheme Core Value and Optimization Suggestions
(A) Core Value
Maximized Powertrain Efficiency: The combination of SJ technology for HV and ultra-low Rds(on) for LV systems minimizes total energy loss, directly translating to increased payload or range.
Uncompromising Safety & Reliability: The selected devices, with their robust packages and voltage ratings, form the foundation for fault-tolerant electrical systems meeting aerospace-grade safety standards.
Optimized Power-to-Weight Ratio: High-current density devices (like VBNC1303) and efficient high-voltage switches reduce the need for excessive paralleling and cooling mass, contributing to overall vehicle weight reduction.
(B) Optimization Suggestions
Higher Power Propulsion: For motors exceeding 100kW per phase leg, consider parallel configurations of higher-current SJ MOSFETs (e.g., 30A+ variants in TO-247) or evaluate SiC MOSFETs for the ultimate efficiency and frequency advantage.
Integration & Monitoring: For auxiliary systems, use intelligent power switches (IPDs) that integrate drive, protection, and diagnostic feedback. For safety isolation, consider VBP2205N in conjunction with integrated current-sense amplifiers.
Specialized Variants: Seek "QML" (Qualified Manufacturers List) or automotive-grade AEC-Q101 qualified versions of these parts for enhanced reliability screening and traceability.
Redundant Actuation: For flight-critical actuators, design dual-channel drives using devices like VBNC1303, each with independent power and control paths.
Conclusion
MOSFET selection is central to realizing the demanding performance, safety, and efficiency targets of AI-driven inter-city eVTOL aircraft. This scenario-based strategy, utilizing the VBM165R15S for propulsion, VBP2205N for safety isolation, and VBNC1303 for high-power auxiliary systems, provides a robust technical foundation. Future development will naturally evolve towards wide-bandgap (SiC, GaN) solutions and highly integrated smart power modules, pushing the boundaries of power density and intelligence to enable the next generation of sustainable urban air mobility.

Detailed Scenario Topology Diagrams