Understanding Smart Sensors - Nomads.usp

384 Understanding Smart SensorsPersonal ID smart sensor, 324–25PhoneDucer, 300Photomicrographsmicrocontroller with integrated pressuresensor, 323micromachined piezoresistive pressuresensor, 83pressure sensor die, 12Piezoelectric sensors, 59–60defined, 59illustrated, 60surface machining, 59Piezoresistive pressure sensorsintegrated, 85with integrated resistor network, 83monolithic, 39noise, 65–66output curve, 51temperature effect on output, 6Wheatstone bridge, 51Piezoresistivitydefined, 50in silicon, 52–54Pin grid array (PGA) package, 228Plasma etching, 32–34defined, 32manufacturing control, 34See also EtchingPlastic packaging, 236reliability, 241uses, 236Plug-and-play, 297–300Point-to-point communication, 120, 122Polymer films, 42–43Power ICs (PICs), 250current sensing in, 256eight-output, 254Profibus protocol, 132, 142defined, 132Ethernet and, 142Programmable logic controllers(PLCs), 149, 150Programmable logic devices (PLDs), 93Proportional-integral-derivative (PID)control, 149, 150–54algorithm, 153fuzzy logic vs., 155illustrated, 153See also ControlProtocolsautomotive, 123–30building/office automation, 124–25defined, 120home automation, 125industrial, 124in market segments, 124–25MCU, 143MI-Bus, 141–42as modules, 145–46multimaster, 127in silicon, 135–42SPI, 143TCP/IP, 303–4transition between, 143–44See also CommunicationsPulse-width modulation (PWM), 66control, 108–9output pressure sensor schematic, 110output pulse width, 109Quadrature direction sensing, 63detection illustration, 64output, 64Quadrature phase shift keying (QPSK), 179Queued SPI (QSPI), 143Radar, 183–85defined, 183microwave sensor transceiver, 185proximity sensor, 184sensor schematic, 185See also RF sensingRadio frequency (RF)applications, 175to digital transition, 176interference (RFI) reduction, 111–12ISM bands, 174MEMS, 195–96in remote sensing, 173signal strength measurements, 192spectrum, 174–77Rail-to-rail operational simplifiers, 76–77RAM, 97dynamic, 97ferroelectric (FeRAM), 98static, 97See also Memory