by Bill Schweber @ digikey.com:
With very few exceptions, every electronic circuit needs an oscillator, also referred to as a clock, clock generator, or timing circuit. Its role is to provide the “heartbeat” for the processor, memory functions, communications ports, A/D and D/A converters (if any) and many other functions. In non-critical, low-budget situations such as $10 mass-market electronic thermometers, this clock may be made from a simple resistor/capacitor (RC) oscillator. However, for the vast majority of situations which are more critical, the oscillator is based on a quartz crystal (Figure 1). This is a mature (80+ years) and highly effective technology which can support of wide range of frequencies from kHz to hundreds of MHz, with performance spanning fairly good to excellent, depending on the crystal cut, fabrication, packaging, and other considerations.
MEMS Oscillators Challenge Quartz Crystals in RF Applications - [Link]
by Graham Prophet @ edn.com:
STMicroelectronics’ MP23AB02B MEMS microphone maintains ultra-low distortion at less than 10% up to very high external sound-pressure levels, enabling equipment such as smartphones and wearable devices to perform better when placing calls or recording audio in loud environments.
With acoustic overload level of 125 dB SPL and signal-to-noise ratio of 64 dBA, the 3.35 x 2.5 x 0.98-mm microphone employes ST’s dedicated preamplifier design, which prevents saturation of the output signal even when background-noise levels are high, such as in concert venues, bars or clubs, or if the user is speaking loudly close to the microphone. In addition, omnidirectional sensitivity ensures overall performance and versatility in mobile applications.
Smart MEMS mic hears better in loud environments - [Link]
SiTime SiT8008 is a programmable MEMS oscillator reaching quartz precision but with higher reliability and lower g-sensitivity. Also SiTime is one of companies who received investments from Rosnano – Russian high-tech investment fund.
The trick is that to reach maximum Q-factor (up to ~186’000 according to patents) MEMS resonator must operate in vacuum. So they package resonator _inside_ the die in hydrogen atmosphere, then anneal it in vacuum so that hydrogen escapes through silicon. So we see here only a cap with contacts to “buried” MEMS resonator. We were unable to reach the resonator itself without x-ray camera or ion mill.
SiTime SiT8008 – MEMS oscillator : die-shot - [Link]
by Steve Taranovich:
I recently spoke to Piyush Sevalia, Executive Vice President, Marketing at SiTime Corporation,about their newly introduced 32 kHz TCXO (temperature compensated oscillator) which they claim to be the smallest, lowest power device in the industry. With its tiny footprint and ultra-low power consumption, the SiT1552 MEMS TCXO decreases the size and increases battery life of wearable electronics and Internet of Things (IoT); such benefits are not achievable from legacy quartz devices.
SiTime enters wearables, IoT markets with 32 kHz MEMS TCXO - [Link]
by John Widder & Alessandro Morcelli :
The application of MEMS (Micro Electro-Mechanical Systems) technology to microphones has led to the development of small microphones with very high performance. MEMS microphones offer high SNR, low power consumption, good sensitivity, and are available in very small packages that are fully compatible with surface mount assembly processes. MEMS microphones exhibit almost no change in performance after reflow soldering and have excellent temperature characteristics.
Basic principles of MEMS microphones - [Link]
The era of the MEMS switch may finally be here thanks to the research efforts of GE. Its MEMS chip, as small as 50 microns square, swathes as fast as 3 GHz and can handle up to 5-kiloWatts of power, making it a candidate for everything from industrial power control, to turning on light bulbs to switching antennas inside a smartphone.
MEMS Switch from GE claims fastest/highest Power Crown - [Link]
Invensense MPU6050 is an integrated gyroscope and accelerometer with 16-bit readings. It contains 2 dies, soldered face-to-face in multiple places (that’s what was causing us troubles last time!).
On the overview photo you can see how not-flat they are. On a bigger die MEMS part is 28µm above surface, on smaller die – 100 µm above. Also, there is logic right under MEMS on the bigger die.
Invensense MPU6050 6-axis MEMS IMU die-shot - [Link]
The broad benefit of MEMS technology is that it will allow high-volume, small-package technology and batch semiconductor manufacturing to replace the complex manufacturing processes associated with quartz. Since the final product is a silicon die, MEMS can be co-packaged (overmolded) with associated ICs, enabling further benefits in manufacturability, size, compatibly, ease-of-use, and, of course, lower total system cost. Finally, MEMS is more immune to shock, vibration, and electromagnetic interference (EMI) than quartz; can be designed to be free of “activity dips”; and can support operating temperature ranges beyond -40°C to +85°C. (by Todd Borkowski)
Time for a change: Quartz oscillators make way for MEMS - [Link]