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Digital Circuits and Logic Design



                   Notes
                                   alarms, mobile electronics, global positioning systems, elevator controls, patient monitoring
                                   devices and head-mounted displays for gaming.

                                   MEMS Designs, CMOS Fabrication
                                   To take advantage of lower fabrication costs, MEMSIC designs its sensors almost exclusively
                                   with standard CMOS layers: for example, the heater is gate polysilicon and the first layer of
                                   the thermopile is metal and polysilicon.

                                   “We have a tremendous advantage over our competitors,” continues Yongyao. “Our process
                                   is almost independent of the fabrication foundry because our design is 95-99% CMOS. We
                                   can easily change process and foundry to take advantage of better production pricing. Our
                                   competitors, on the other hand, use proprietary MEMS processes, fabricating either by
                                   themselves or through a specialized foundry, and that is always more expensive than working
                                   with a traditional CMOS foundry.”
                                   MEMSIC also enjoys an advantage when changing geometry. Most of its competitors are still
                                   producing at 1-2 micron, and a change to .25 micron in MEMS would result in a completely
                                   different process and a costly conversion. MEMSIC has produced in .6 and .25 micron—with
                                   .18 micron on the roadmap—and its standard CMOS IC process allows it to ramp up volume
                                   and production quickly after a change in geometry.
                                   92,000 Accelerometers in Beijing
                                   The marquee application of MEMSIC’s technology was in the electronic “Waving Torch”
                                   distributed to all attendees of the opening ceremonies for the 2008 Olympics in Beijing.
                                   The torch resembles a 20-30cm wand, with a linear array of LEDs. Shaken from side to side,
                                   the torch tricks the human eye into seeing iconic Olympic images—symbols for major sports,
                                   the Olympic logo, Chinese greetings, and the five Olympic mascots—displayed in mid-air as
                                   the LEDs switch on and off. The core technology in the torch includes a MEMSIC algorithm
                                   and accelerometer (designed with Tanner tools) to detect the user’s back-and-forth hand
                                   movement and to fire each LED as needed for the image.
                                   “We worked on this project for half a year as an Olympic promotional tool,” says Yongyao.
                                   “The user waves the torch through the air, and the LEDs display the pattern according to
                                   the motion. It is a good example of how much information an accelerometer can provide on
                                   position, orientation and speed.”
                                   About MEMSIC

                                   MEMSIC, Inc. designs, manufactures and markets CMOS Micro-Electro-Mechanical Systems
                                   (MEMS) IC products that have on-chip mixed signal processing. MEMSIC is the first and the
                                   only company that integrates a MEMS inertial sensor with mixed signal processing circuitry
                                   onto a single chip using a standard CMOS IC process. This combination of technology has
                                   successfully yielded products at substantially lower cost and higher system performance
                                   and functionality than competitive products in the market for sophisticated accelerometers.
                                   In addition, this technological approach allows the Company to easily integrate additional
                                   functions, or create new sensors, using a standard CMOS IC process to expand into other
                                   MEMS application areas beyond accelerometers.
                                   The Company’s accelerometers, sometimes called inertial sensors, are used to measure tilt
                                   or inclination, shock or vibration, or inertial acceleration. Any application that requires the
                                   control or measurement of motion is a potential application for accelerometers.
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