Alpha and Omega Semiconductor Introduces Auto-Grade MOSFETs
Electric vehicles need components that can withstand extreme temperatures and harsh weather conditions. Alpha and Omega Semiconductor’s new MOSFETs offer high performance and ruggedness.
The emergence of electric vehicles (EVs) is transforming the automotive industry. The development of EV systems has relied on more performant, efficient, and robust power electronic systems that can handle harsh automotive conditions.
Alpha and Omega Semiconductor’s MOSFETs for electric vehicles. Image used courtesy of Alpha and Omega Semiconductor
Recently, Alpha and Omega Semiconductor introduced automotive-grade 80 V and 100 V MOSFETs to the market, hoping to improve electric vehicle performance and efficiency. This article examines the details of those two products, the AOTL66810Q and AOTL66912Q.
Figure of Merit (FOM)
The Figure of Merit (FOM) for MOSFETs is a crucial specification, playing a pivotal role in providing comparisons and evaluations of the efficiency and performance of these semiconductors. In essence, the FOM of a MOSFET is a measure that combines several key parameters into a single value, enabling a more straightforward assessment of the transistor's overall performance.
Loss and efficiency data for MOSFETs with different FOMs in a ZVS bridge converter switching at 200 kHz. Image by EEPower
One commonly used FOM is the product of the MOSFET’s on-resistance and its gate charge. The on-resistance represents the resistance between the drain and source terminals when the MOSFET is in the “on” state. Lower Rds(on) is desirable as it reduces power loss due to heat, thereby improving efficiency. The gate charge, on the other hand, is the amount of charge required to turn the transistor on and off. A lower gate charge translates to faster switching speeds and reduced power consumption during the switching process.
The on-resistance and gate charge product provides a balanced view of a MOSFET’s efficiency by considering both static and dynamic losses. Static losses occur due to the resistance when current flows through the device, while dynamic losses are associated with the energy required to switch the device on and off. A lower FOM value indicates a more efficient MOSFET capable of providing high performance with less power loss.
Closeup of AOTL66810Q
The AOTL66810Q is an 80 V N-Channel MOSFET designed for automotive applications.
On-resistance versus gate-source voltage of the AOTL66810Q. Image used courtesy of Alpha and Omega Semiconductor
One noteworthy feature of the device is its excellent Figure of Merit, with a typical gate charge of 175 nC and an Rds(on) as low as 1.25 mΩ at V_GS = 10 V. The MOSFET also boasts a drain-source current of 445 A and a pulsed drain current of 1780 A.
Its robust design has allowed it an AEC-Q101 qualification thanks to specifications like a maximum junction temperature of 175°C to meet the rigorous conditions of automotive environments. With these specifications, this MOSFET is intended for applications in BLDC motor drives, battery management, and as a load switch.
Details of AOTL66912Q
The AOTL66912Q is a 100 V N-Channel MOSFET that shares many of the high-performance characteristics of the AOTL66810Q.
On-resistance versus gate-source voltage of the AOTL66912Q. Image used courtesy of Alpha and Omega Semiconductor
Rated for 100V VDS, this FET features an Rds(on) as low as 1.7 mΩ and a typical total gate charge of 155 nC, making for an impressive FOM. This MOSFET is also AEC-Q101 qualified and features a maximum drain-source current of 370 A and a pulsed drain current of 1480 A. Other notable specifications include a maximum power dissipation of 500 W @ 25 C and an avalanche current of 90 A.
Similar to the AOTL66912Q is designed for applications such as BLDC motor drives and battery management systems. It can also sustain a maximum junction temperature of 175°C, confirming its endurance in challenging automotive environments.
Electric Mobility and MOSFETs
As electric mobility continues to evolve, innovations in power MOSFETs will be necessary for more efficient and safe systems. The introduction of the AOTL66810Q and AOTL66912Q MOSFETs by Alpha and Omega Semiconductor marks an advancement in the field. With their robust thermal and electrical characteristics, these components are poised to enhance the performance and efficiency of electric vehicles.
