Integrated Device Technology (IDT), has recently released its new piezoelectric MEMS, or pMEMS, based oscillators. According to the company, crystal oscillators are complicated to manufacture and unreliable compared to pMEMS. IDT's new devices are more convenient, accurate and feature low-jitter timing references – perfect, IDT says, for communications, consumer, cloud computing and industrial applications. We recently spoke with Harmeet Bhugra, Managing Director of the MEMS division of IDT. In this interview, Harmeet compares pMEMS technology to crystal oscillators, as well as other types of MEMS based timing solutions.
MEMS Journal: What are pMEMS are and how they differ from traditional MEMS oscillators?
Harmeet Bhugra: pMEMS are piezoelectrically actuated MEMS resonators. Traditional MEMS resonators are capacitively actuated – in other words, they require a DC bias voltage across the electrode gap to capacitively induce resonance. pMEMS resonators are passive – that is, no DC bias voltage is required, no electrode gaps are required, and no stiction related reliability issues are present.
MJ: What are some of the other difference of pMEMS oscillators to other types of MEMS oscillators?
Bhugra: pMEMS oscillators take advantage of high native frequency of the pMEMS resonator to deliver world class jitter performance. In addition, these oscillators use the world’s smallest wafer level packaged resonators to enable a cost-effective solution. Since there are no gaps needed for actuation, the reliability of these products is higher since we do not suffer from any stiction issues.
Comparison of pMEMS and capacitive MEMS oscillators. (Source: Integrated Device Technology, Inc.)
MJ: What are the drawbacks of pMEMS oscillators?
Bhugra: None that I am aware of. There are always performance tradeoffs for each type of oscillator that have to be balanced such as frequency, jitter, power and packaging. All of these variables are, and can be, optimized on purpose for each targeted application.
MJ: Has IDT really developed the "world's first" pMEMS device? How and why did IDT decide to pioneer this technology?
Bhugra: IDT has developed world’s first commercially available pMEMS resonators. IDT licensed the initial technology from Georgia Institute of technology and started pMEMS development in 2007. We decided to pursue developing pMEMS technology instead of the capacitive MEMS resonators to overcome the limitations posed by capacitive MEMS devices specifically around performance, manufacturability and reliability. In addition, pMEMS resonators allowed IDT to develop higher native frequency resonators compared to quartz resonators and capacitive MEMS resonators. Also, pMEMS resonators have a lower motional impedance which allows IDT to offer higher performance products.
MJ: How do pMEMS oscillators compare to IC timing devices from IDT (formerly Mobius)?
Bhugra: IDT’s CMOS harmonic devices are well suited for low-power applications. pMEMS solutions are better suited for high performance applications requiring better frequency accuracy as well sub-ps jitter performance.
MJ: How do pMEMS oscillators compare to traditional quartz based oscillators?
Bhugra: pMEMS oscillators have demonstrated better jitter performance and better reliability for the final product. In fact, we have measured long-term stability of the pMEMS resonators for over two years under different stressed conditions and IDT pMEMS resonators significantly outperform crystal resonator stability.
MJ: What kind of technological leap was necessary to make pMEMS a reality?
Bhugra: We had to make pMEMS products manufacturable. No one had demonstrated that the technical challenges could be overcome. At the same time, it was important to manage tradeoffs between performance and cost effectiveness without compromising on quality and reliability. IDT ended up developing not only world’s first but the world’s smallest wafer level packaged pMEMS resonators.
MJ: You're sampling to customers now. When do you hope to begin large-scale manufacturing?
Bhugra: IDT has been working with advanced customers for some time and we expect to begin large scale manufacturing in the next few months.
MJ: You probably cannot reveal who your current customers are and who you are courting as future customers, but can you tell us generally what kinds of applications or industries they are in?
Bhugra: Applications vary from networking such as 10GbE/switches/routers, to consumer applications such as printers, to industrial applications such as robotics, and storage applications such as SSD controllers.
MJ: For which specific applications are pMEMS oscillators the best match? Why?
Bhugra: Initial pMEMS LVPECL/LVDS output oscillators are best suited for applications requiring sub-ps jitter such as networking and communications. Also, these products serve a variety of end markets from communications, consumer, cloud computing, and industrial applications. These products best serve the high performance applications requiring jitter of less than 1 picosecond, and applications that require high reliability and resistance to shock and vibration.
MJ: How large of a market do you foresee for pMEMS?
Bhugra: pMEMS timing market is expected to be a few hundred million dollars.
MJ: What is this estimate based on?
Bhugra: This estimate is based on analyst reports published by CS&A, iSuppli and Yole for MEMS frequency references.
MJ: What is the price range for the product?
Bhugra: Pricing depends on product configuration and volumes. In general, prices are either comparable with XOs or little lower than XOs.
MJ: How are you able to produce this product at a lower cost?
Bhugra: We are using world’s smallest wafer level packaged resonators and also by leveraging IDT’s expertise in semiconductor manufacturing capabilities.
*********************************************
This article is a part of MEMS Journal's ongoing market research project in the area of MEMS oscillators. If you would like to receive our comprehensive market research report on this topic, please contact Dr. Mike Pinelis at mike@memsjournal.com for more information about rates and report contents.
Copyright 2012 MEMS Journal, Inc.
Comments