The Latest Products for Wearable Devices

In recent years, with the increased sophistication and functionality of devices such as smartphones and tablets comes a greater demand for smaller, thinner products at the component level that also provide high reliability and precision. Furthermore, the growing popularity of wearable devices has spurred a need for even more compact, lower profile components that provide ultra-low power consumption.

To meet this need, ROHM has developed the RASMID® series (ROHM Advanced Smart Micro Device) of ultra-compact electronic components. This new series, which includes the world’s smallest transistors, diodes, capacitors, and LEDs, utilizes novel technologies and processes that break from convention to achieve unprecedented dimensional accuracy and miniaturization. In 2011 ROHM debuted 03015-size (0.3mmx0.15mm) chip resistors that reduce footprint by 44% over the conventional 0402 size, and in 2012 introduced the smallest discrete semiconductor products in the industry: 0402-size Zener diodes. Then in 2014 ROHM expanded its lineup of market-leading ultra-compact components by offering 0402-size Schottky barrier diodes, and soon began mass production of 03015-size chip resistors. （See Figure 1）

Figure 1. RASMID^® Series 0402-Size Diode and 03015-Size Chip Resistor

It should be noted that with the RASMID^® series, ROHM is not simply pursuing device miniaturization, but implementing technology development to promote practical realization, including mounting technology.

In addition to this lineup, ROHM developed the world’s smallest transistors (VML0604 package) in March 2014, measuring just 0.6mm x 0.4mm (t=0.36mm), for applications requiring thinner, smaller form factors, such as wearable devices and smartphones – utilizing cutting-edge package and element processes. （See Figure 2）

Figure 2. Package Comparison: Conventional VML0806 vs. New VML0604

This new series of ultra-compact transistors features the lowest ON resistance in the 30V class* (0.25Ω @ VGS=4.5V) and provides higher breakdown voltages than conventional models while maintaining low ON resistance. 40-60V products are currently being added to the lineup. （See Figure 3）

Figure 3: The Industry’s Lowest ON Resistance: 0.25Ω at V_GS=4.5V

ROHM expects that these ultra-small products, along with its market-leading small-signal transistors and diodes, will have a major impact in the emerging wearable device market.

Besides greater miniaturization, there is a growing need for lower power consumption in order to prolong battery life in portable applications that feature ever-increasing performance and functionality. With this comes a shift towards the adoption of Bluetooth^® Low Energy (BLE) in a variety of products. Compared to standard Bluetooth, BLE features considerably lower power consumption while maintaining communication distance. It is also natively supported by most smartphones and is expected to be widely adopted by portable devices in the health & fitness, security, and consumer industries.

In response, LAPIS Semiconductor, a ROHM Group Company, has developed a BLE-compatible IC (ML7105-00x) for the wearable device sector featuring class-leading low current consumption (9.8mA during transmission, 8.9mA during reception, 8uA average current during 2-second intermittent operation). （See Figure 4）

Figure 4. Power Consumption Comparison: ML7105 (Existing) vs. ML7105-00x (New)

]LAPIS Semiconductor is also currently developing a module that is Bluetooth SiG certified and complies with radio standards in Japan and other countries, as well as products that feature greater ease-of-use. （See Figure 5）

Figure 5. Image and Block Diagram of a BLE Module Currently Under Development

Along with these products, ROHM anticipates an increased demand for a variety of sensors, such as proximity and ambient light sensors, accelerometers, and magnetometers, as well as LAPIS Semiconductor’s low power microcontrollers. Going forward, ROHM will continue to develop smaller, lower power consumption devices and solutions that maximize performance and bring added value.