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High-stability TCXOs aim at mobile GPS market

Posted: 18 Jul 2008 ?? ?Print Version ?Bookmark and Share

Keywords:temperature compensated crystal oscillators? TCXOs? mobile GPS terminal market?


Epson Toyocom Corp. has begun volume production of crystal products that employ the company's photo AT chips. The photo AT chips, fabricated using QMEMS technology, are being provided in Epson Toyocom's ultraminiature, frequency-stable TG-5005CG series of temperature compensated crystal oscillators (TCXOs) for the mobile GPS terminal market.

The market for GPS capability in mobile terminals has been expanding in recent years, as GPS technology enables applications that, for example, allow the location of a cellphone 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 ultraminiature, high-stability TCXOs, which measure 2.5mm x 2mm x 0.9mm 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 ultraminiature 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 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.

The devices offer an output frequency of 13-40MHz and has a frequency tolerance of2 x 10-6 (max). Other features include a frequency/temperature coefficient of 0.5 x 10-6 (max).

Operating temperature range is from -30C to +85C

Supply voltage (standard)is 2.8V

The TG-5005CG is Pb-free and EU RoHS compliant.

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