10:36Small varistors and CeraDiodes
Epcos offers CeraDiodes and multilayer varistors (MLV) in a 0201 package. The variants with capacitances of 22 pF are distinguished by a low clamping voltage and are suited for the protection of LED background lighting, for example. Types with capacitances of up to 10 pF have also been developed for USB and Ethernet systems. Because of the need to minimize parasitic capacitances, especially in RF technology, Epcos is developing a special antenna varistor with a capacitance of less than 1 pF.
Integrated ESD/EMI filters comply fully with the trend toward miniaturization and integration of components designed specifically for mobile phones. The company has developed two types of ESD/EMI filter arrays. The 0405 audio filter protects microphone and loudspeaker leads from ESD damage and interference, and RC filters in 0508 and 0306 packages were developed to protect display lines. While the audio filter replaces ten discrete components, the RC filter takes the place of twenty components packed in a single package.
10:33Piezo resonator for 2.8V
Epcos has developed a series of miniaturized multilayer piezo components. In addition to the piezo transformers already on the market, the company now offers piezo benders and resonators. The latter has allowed US company New Scale Technologies to develop the world’s smallest linear motor that is powered directly by a battery voltage of 2.8 V. With a length of 6 mm, its height and width are just 1.55 mm². The motor consists of a threaded pin running inside a threaded nut. Activating the ultrasonic resonator causes the nut to oscillate torsionally and drive the threaded pin forward and back. This simple and rugged construction allows forward speeds of up to 10 mm/s with a resolution as fine as 0.5 μm to be attained. The operating frequency of the piezo resonators is in the ultrasound range of 150 kHz. Previous piezo-based linear motors require an operating voltage of about 30 V. By contrast, the new piezo resonators from EPCOS require just 2.8 V. In combination with its compact dimensions, it is suitable for use in battery-powered devices. One possible application is an optical zoom plus autofocus for camera systems in mobile phones.
