MOSFET Report: New Devices Lower Losses and Boost Power Density

Metal-oxide-semiconductor field-effect transistors (MOSFETs) have been at the heart of digital and power electronics for decades, and they continually face challenges as technology advances. One of the most pressing issues for MOSFETs is that they must operate at high-voltage levels while remaining reliable. Manufacturers must carefully choose insulating materials and techniques that ensure safe operation at elevated voltage levels.

This article discusses some late Summer announcements of MOSFETs designed to tackle power electronics system challenges.

 

AOS Package Technology Reduces ON Resistance 

Alpha and Omega Semiconductor (AOS) introduced its new packaging technology, MRigidCSP, for MOSFETs in battery management applications. The new packaging decreases ON resistance and increases the mechanical strength of its new 12 V N-channel MOSFET, AOCR33105E (datasheet linked).

 

AOS says its MRigidCSP packaging technology is particularly advantageous for fast charging. Image (modified) used courtesy of Alpha and Omega Semiconductor

 

In standard wafer-level, chip-scale packages, the substrate is responsible for a significant portion of the total resistance when back-to-back MOSFETs are used in battery management applications. A thinner substrate reduces the overall resistance but also reduces the mechanical strength. The new packaging technology involves trench-power technology in a simple common-drain configuration. It features ultra-low ON resistance with ESD protection and also increases the mechanical strength of the device.

The company specifies the target application for these MOSFETs in battery management systems for smartphones, tablets, and ultra-thin notebooks.

 

Toshiba Releases 2,200V Dual SiC MOSFET Module

Toshiba announced its new 2,200 V dual silicon carbide (SiC) MOSFET MG250YD2YMS3 (datasheet linked) for industrial equipment. It features a current rating of 250 A and suits applications using 1,500 V DC and above, like photovoltaic and energy storage systems.

Industrial applications generally use power devices rated at 1,200–1,700 V, and Toshiba anticipates a widespread use for 1,500 V_DC voltage levels and above. One of the primary advantages of using higher voltage-rated devices is that they reduce conduction losses. In such devices, the voltage drop across the device is proportionally smaller for the same current.

While higher voltage devices may have slightly higher gate capacitance, they can also have lower switching losses because of the faster switching speeds. The device's larger die area and the ability to handle higher gate currents also enable quicker transitions between the ON and OFF states. 

 

High-side and low-side inductive load switching test circuits. Image used courtesy of Toshiba

 

Beyond lower conduction and switching losses, Toshiba's new MOSFET offers a very low drain-source voltage of 0.7 V. It reduces the switching loss by approximately 90% compared to silicon IGBTs, allowing for compact circuits and higher equipment efficiency.

 

Vishay Unveils Power MOSFETs for High-Power Density

Vishay introduced a fourth-generation 650 V E-Series power MOSFET featuring ultra-low ON resistance gate charge time. This new lineup reduces ON resistance by 48.2% and ON resistance gate charge times by 59% compared to previous generations, making them useful for edge computing, servers, data storage, UPS, motor drives, and other similar applications.

 

The new SiHP054N65E power MOSFET. Image used courtesy of Vishay

 

Thanks to the company's latest E-series super junction technology, new MOSFETs like SiHP054N65E (datasheet linked) offer a typical ON resistance of only 0.051 Ω at 10 V and a low gate charge of 72 nC, making it slightly better than the closest competing MOSFET. They also feature low output capacitances and are designed to withstand overvoltage transients in avalanche mode.

 

MOSFETs Keep Pace With Power Demands

MOSFETs face several challenges in modern power systems: they require dedicated gate drivers, incur high manufacturing costs, and demand high integration, fast switching speeds, and high power dissipation. Efficiency and ON resistance are of the highest concern. Power MOSFETs must have low ON resistance to minimize power loss. Low ON resistance reduces conduction losses, resulting in increased efficiency. Achieving low ON resistance, however, involves intricate structural design and optimized materials.

Component manufacturers like AOS, Toshiba, and Vishay are exploring new materials, device structures, and packaging techniques to overcome these challenges. Advances in wide-bandgap materials, like silicon carbide (SiC) and gallium nitride (GaN), also help address some obstacles by providing superior performance and efficiency in high-power applications.