Epson Toyocom Expands "QMEMS" Photo AT Chip Product Lineup

Production begins on ultra-miniature, high-stability TG-5005CG TCXOs equipped with photo AT chips for mobile GPS terminals.

Epson Toyocom Corporation, the leader in crystal devices, has begun volume production of crystal products that employ the company’s photo AT chips. The photo AT chips, fabricated using QMEMS*1 technology, are being provided in Epson Toyocom’s ultra-miniature, frequency-stable TG-5005CG series of TCXOs (temperature compensated crystal oscillators)*2 for the mobile GPS terminal market.


The market for GPS (global positioning system) capability in mobile terminals has been expanding in recent years, as GPS technology enables applications that, for example, allow the location of a cell phone to be pinpointed in the event of an emergency call. This expansion is driving demand for the tiny, frequency-stable TCXOs that are essential for accurately determining position.


Epson Toyocom had been meeting this demand with its TG-5005CG series of ultra-miniature, high-stability TCXOs, which measure just 2.5 x 2.0 mm and have a frequency-temperature characteristic (an indicator of frequency stability over a temperature range and, thus, accuracy) of ±0.5 x 10-6. However, to achieve even higher stability and throughput, Epson Toyocom is now leveraging its proprietary QMEMS technology to fabricate photo AT chips for the TG-5005CG series. Despite their diminutive size, photo AT chips offer outstanding frequency stability, with very little variation in characteristics. Volume production of the TG-5005CG high-stability TCXOs equipped with the photo AT chips is now underway.


In the past, steps taken to limit variation in the characteristics of crystal oscillating elements adversely affected crystal characteristics and hindered production efficiency, as variations had to be offset by, for example, tuning oscillation circuits according to the characteristics of each crystal chip.


Now, by leveraging its proprietary QMEMS technology to fabricate ultra-miniature photo AT chips that, despite their size, are frequency stable and have nearly uniform characteristics, Epson Toyocom is able to limit variation. Using these photo AT chips, the company has realized TCXOs that have minute activity dips*3 and that maintain extremely high stability even when exposed to temperature fluctuations, physical shocks or other changes in the external environment when receiving GPS signals. These oscillators can also be produced efficiently and with high throughput, enabling Epson Toyocom to ship in stable quantities.


Market demand for even smaller TCXOs with even better frequency stability are expected to escalate in the future. Using QMEMS technology as a technology driver, Epson Toyocom will stay on top of this demand and contribute to the further development of mobile terminals equipped with GPS capability.

Glossary

*1 QMEMS

QMEMS is a combination of “Quartz,” a crystalline material with excellent characteristics such as high stability and high precision, and “MEMS” (micro electro mechanical system). QMEMS quartz devices are created using quartz material instead of the semiconductors used by MEMS. We perform precision microfabrication on the quartz material to offer high performance in a compact package.
QMEMS is a registered trademark of Epson Toyocom.


*2 TCXO (Temperature Compensated X’tal Oscillator)

A high-stability oscillator with embedded temperature-compensation circuitry that minimizes changes in frequency caused by changes in temperature


*3 activity dip

An abrupt change in the resonant frequency and series resistance of a crystal unit observed when an uninterrupted temperature change is applied to the crystal unit (crystal chip)