▲During the webinar on 'MOSFET Selection and Use Method'


ROHM shares MOSFET basics, characteristics, and precautions at e4ds webinar
Introducing ROHM DFN Wafer Level Chip Size Package Series

ROHM (hereinafter referred to as ROHM) shared basic knowledge and characteristics of MOSFETs, which are increasing due to the automotive electrification trend, along with information on ROHM's MOSFET products.

On the 1st, Tae-Hyun Ho, a researcher at ROHM, held a webinar at e4ds on the topic of 'MOSFET selection and usage methods' and introduced the characteristics of MOSFETs as well as ROHM's new DFN series products that satisfy high efficiency and miniaturization.

MOSFETs are devices that feature high-speed switching and low loss compared to bipolar transistors, and are used in a wide range of fields, including electronic devices including automotive equipment, power circuits, and motor drive circuits.

As automotive electrification, represented by ADAS, accelerates further, the use of MOSFETs is also expected to increase.

In addition, as demand for eco-friendly products has increased due to recent environmental issues, demand for high-efficiency products with low loss is increasing for MOSFETs, and as space constraints are becoming more severe due to electrification of various devices, demand for small package products is also increasing.

When the MOSFET is ON, the electrical current between the drain and the source The resistance value is called ON resistance and is represented by the symbol R DS(ON) . The lower the ON resistance value, the less loss there is during operation.

Since the ON resistance of MOSFETs is generally less than ohms (Ω), they consume less power than transistors and can simplify circuit heat dissipation measures.

The gate-source voltage also changes depending on the current, so when improving power loss, the ON resistance value considering the gate-source voltage and drain current must be used for calculation.

ON resistance also varies with temperature, so caution is required.

In general, the larger the MOSFET chip size, the smaller the ON resistance.

As the package size gets larger, the size of the chip that can be mounted also gets larger, so the ON resistance tends to get smaller.

Gate threshold voltage is the gate voltage at which the MOSFET starts to turn ON and is denoted by V _GSth .

When a voltage above the threshold is applied, the MOSFET turns on.

The current required to turn the MOSFET ON varies by product, so you should check the electrical characteristics section of the specification sheet.

In addition to the characteristics above, researcher Taehyun Ho shared various characteristics and precautions, such as the SOA (Safety Operation Area) and ESD (Electro-Static Discharge) of MOSFETs.

He then introduced ROHM's MOSFETs, which feature low ON resistance and high-speed switching, and said that they can be selected for various applications such as automobiles, industrial equipment, and power motors.

In addition, future market demands will increaseWe are expanding our lineup with DFN series products for small, high-current products that are expected to be used, and CSP type wafer-level chip size package series.

▲During the webinar on 'MOSFET Selection and Use Method'

Unlike conventional lead-type packages, the DFN package product is a back-electrode product that can mount a chip of the same size as a SOT-23 in a 1 mm x 1 mm package, reducing the size of the finished product by 85%.

In addition, heat dissipation is improved by 65% compared to SOT-23, realizing both miniaturization and high heat dissipation, and can also respond to high-density substrates.

Originally, DFN products were double-sided electrode products, so solder fillets were not formed and were not used for automotive applications that required high reliability.

ROHM also supplies products with Wettable Flank processing so that they can be used for automotive applications.

Plating is applied to the side of the lead frame so that a solder fillet is formed during mounting, allowing the mounting status to be confirmed through AOI inspection.

Next, researcher Tae-Hyung Ho talked about WL (wafer level) CSP type products.

As small devices become more functional, the amount of power required within the device increases, and the size of the battery increases accordingly, reducing the mounting space of the product.

Since there is a limit to the size of the battery, a built-in battery charger is used to efficiently use the limited battery power.Components are required to have even stronger power loss suppression.

In this market situation, the industry is focusing on development of MOSFETs that are easy to miniaturize and have superior characteristics using wafer-level chip size packages.

Products that adopt wafer-level chip size can secure a wider active area than existing products, and can flow a current of 3 amperes even in a small size.

Also, compared to the DSN1006, the ON resistance is very low, one-third.

ROHM is not stopping there and is also said to be developing an even more compact DSN0403-3.

The webinar 'MOSFET Selection and Usage' conducted by E4ds and ROHM can be viewed again on the EEWebinar page of the e4ds homepage.