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devices to long-term aging (i.e., frequency drift) tests. In these tests, plastic packaged pMEMs resona- tors were placed together with quartz devices in temperature-con- trolled chambers. at 25°c, pMEMs devices have a frequency variation of less than ±2.5 ppm over a period of 21 months, which is better than the typical quartz performance of ±5 ppm – see figure 7. in addition, when tested at Fig. 7: Aging measurements of 10 pMEMS 125°c, pMEMs devices show less resonators over 21 months at 25°C. than ±3 ppm frequency drift over 4500 hours, which is significantly better than the typical quartz mea- surement of ±10 ppm – see figure 8. Finally to demonstrate the perfor- mance of these high-performance sub-ps jitter (12kHz – 20 MHz) pMEMs oscillators in the real world, three applications were imple- mented for networking, Fpga and storage applications as shown be- low. all of these pMEMs application demonstrations have been travelling Fig. 8: Accelerated aging measurements of 10 at various shows around the world – pMEMS resonators over 4500 hours at 125°C. see figure 9. (measurement accuracy ±2ppm). Other advantages of MEMs- based products include natural compatibility with surface-mount assembly processes and short lead times; this enables suppliers and users (electronic manufacturers) to hold smaller device inventory with reduced risk of supply shortages. IDT’s MEMS oscillators support low-voltage differential signaling (LVDS) and low-voltage positive emitter-coupled logic (LVPECL) outputs at frequencies of up to 625MHz, which is required in most communications, networking and high-performance computing ap- plications. Conclusions a new class of pMEMs oscillators has been introduced for high-frequency, low phase noise (<1.0 ps) timing reference applications. The high performance, as well as compactness and stability of the pMEMs devices, has proven this technology to be a cost-effective and more reliable next-generation replacement for quartz crystal oscil- lators for the high-frequency frequency reference applications. Fig. 9: pMEMS oscillators demonstrated in three different applications. www.electronics-eetimes.com Electronic Engineering Times Europe December 2012 37


EETE DECEMBER 2012
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