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www.us-
tech.com
Tiny Components Find Homes in Smaller Circuits MEMS technology, each country
with numerous foundry facilities. MEMS technology is truly far reach-
BE A ABOVE THE REST WITH THE
ing in terms of the applications served by MEMS components, from audio through microwave frequen- cies. For example, the model SPV18 40LR5H-B is a surface-mount micro- phone from Knowles (
www.know
les.com) [and available from distribu- tor Mouser Electronics (
www.mou -
ser.com)] based on the company’s SiSonic silicon-based MEMS technol- ogy. The tiny component consists of an acoustic sensor, a low-noise input buffer amplifier, and an output amplifier. The miniature MEMS microphone, with a wide operating temperature range of –40 to +100°C, runs on less than 5mA current at low voltages for negligible strain on bat- tery power supplies. It has become a popular audio microphone solution for a wide range of consumer elec- tronics applications, including laptop computers, cellular telephones, and portable music recorders.
MEMS Microphone MEMS technology is also the
KAPPA 331
The Kappa 331 sets new, unique benchmarks for
-
komaxwire.com
basis for the model MP23AB02B low- power microphone from STMicroelec - tronics (
www.stmicroelectronics) [also available from Mouser]. This tiny, bottom-port component measures just 3.35 × 2.50 × 0.98 mm in a package with metal cap that is compliant with reflow soldering processes. The silicon micromachining tech -
niques employed to fabricate this com- ponent achieve impressive audio per- formance in such a small package, with a sound pressure level (SPL) of 125dB and a signal-to-noise ratio (SNR) of 64dB measured at 1kHz. The MEMS microphone has an operating temperature range of –40 to +85°C, with straightforward bottom-mounted connections for audio output, ground, and supply voltage. It typically con- sumes only 150µA current from a +1.8VDC supply. Although MEMS technology
has often been thought of as the use of semiconductor fabrication process- es (such as photolithography) to pro- duce miniature machines, it has also been applied to the fabrication of
Silicon MEMS micromachining techniques help form this low-profile audio sensing
element and surface-mount microphone available in
tape-and-reel packaging for automated circuit assembly.
from –40 to +85°C. The RoHS-com- patible oscillator can be readily pro- grammed in the field and features a fast startup time of only 5 ms.
Low Power Operation The low-power operation of such
MEMS components is impressive, and represents another trend in today’s electronic component design and development, for improved ener- gy efficiency. Component designers are continually seeking to develop active and passive components capa- ble of operating at lower voltages and with less energy consumption, notably for longer operating lifetimes in electronic products powered by batteries. Many leading developers of ICs and active components are pur- suing improved energy efficiency for their components, to the extent of reusing energy from other sources in a system (such as electric motors) or by converting sunlight into usable energy. In addition to the conven- ience of providing longer operating times from a single battery charge for personal electronics communica- tions devices, component energy effi- ciency can be a critical performance parameter in the design of some elec- tronic products, such as medical tem- perature and heart-rate sensors and in automotive safety systems. As components are being made
smaller in keeping with the similar miniaturization of semiconductors and other ICs, including data con- verters, field-programmable gate arrays (FPGAs), digital signal pro - cessors (DSPs), and microprocessors, and more energy efficient, another design concern comes into play: keep- ing everything cool. The smaller size of certain active components, such as amplifiers, requires higher energy efficiency to maintain safe thermal conditions. As components and cir- cuits become smaller, thermal man- agement becomes an even more essential part of circuit design and a key to the long-term reliability of future miniaturized components and circuits. r
December, 2015
active components, including oscilla- tors. As an example, SiTime (
www.sitime.com) has applied stan- dard silicon CMOS processing to the formation of reliable clock oscillators. The firm’s model SiT8008B low- power programmable oscillator is available for any frequency from 1 to 110MHz in packages as small as 2.0 × 1.6 mm. The high-stability MEMS oscillator is a low-power replacement for quartz clock oscillators. It draws only 3.5 mA current at +1.8VDC and includes a standby mode for longer battery life. It provides an LVCMOS/ HCMOS-compatible output and is designed for operating temperatures
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