Crystal units are used to generate highly stable reference signals in digital circuits, based on the unique material characteristic of quartz to oscillate at a precise frequency when a specific voltage is applied. The trend toward smaller, more functional smartphones and wearable devices requires smaller, better-performing crystal units.

Traditionally, however, it was believed that miniaturizing crystal units beyond a certain point would compromise their performance, since electrical characteristics (such as equivalent series resistance) degraded as the device became smaller.

However, Kyocera has succeeded in downsizing the crystal unit while maintaining its electrical characteristics — with its current CX1210 (1.2x1.0mm) device, and now, by commercializing the ultra-small CX1008 (1.0x0.8mm) crystal unit. This has been accomplished through crystal element design technology developed exclusively by Kyocera, along with a process that Kyocera developed jointly with Associate Professor Kazuya Yamamura of Osaka University.

Based on this technology, Kyocera will accelerate the development of new low-frequency, high-frequency and high-precision oscillators for such applications as automotive electronics, Advanced Driver Assistance System (ADAS) technologies, IoT devices, wireless network base stations and 5G mobile communications.

With conventional processes and technologies, a crystal unit exhibits higher levels of variation in key electrical characteristics when produced in smaller dimensions. However, Kyocera has avoided this by applying ultra-high-precision processing (plasma CVM technology) developed with Yamamura.

This method, using plasma-generated neutral radicals and a chemical reaction at the surface of an object, enables to control a quartz crystal with highly precise surface conditions and thickness. Further, Kyocera’s proprietary semiconductor processing technology ensures extremely accurate external dimensions, and minimal variation in equivalent series resistance, for optimal performance at reduced size.