Understanding Smart Sensors - Nomads.usp

Getting Sensor Information Into the MCU 91count (full scale) = 229A full-scale pressure of 15 psi with 5.0V supply results in a system resolutionof15 psi /229 = 0.066 psi /count4.5 SummarySeveral circuits and techniques can be used to amplify the low-level output thatis inherently available from sensor or transducer elements. The circuits thatwere discussed are used primarily for interfacing the analog output of the sensorto the digital world of the microcontroller and the DSP. The ongoing industryeffort to improve performance and simplify the interface for sensors either asstandalone units or integrated with the sensors will continue to expand theapplications for sensors in general and simplify the design of future smartsensors.References[1] Dunn, B., and R. Frank, “Guidelines for Choosing a Smart Power Technology,” PCI ’88,Munich, June 6–8, 1988.[2] Klier, G., “Signal Conditioners: A Brief Outline,” Sensors, Jan. 1990, pp. 44–48.[3] Conner, D., “Monolithic Instrumentation Amplifiers,” EDN, Mar. 14, 1991, pp. 82–88.[4] Williams, J., “Good Bridge-Circuit Design Satisfies Gain and Balance Criteria,” EDN,Oct. 25, 1990, pp. 161–174.[5] Schultz, W., “Amplifiers for Semiconductor Pressure Sensors,” Proc. Sensors Expo West,San Jose, CA, Mar. 2–4, 1993, pp. 291–298.[6] Motorola Application Note AN1324, Sensor Device Data/Handbook, DL200/D Rev. 4,1998.[7] Motorola Data Sheet MC33304/D, 1996.[8] McGoldrick, P., “Op Amp Supply Squeezed Down to 1V Rail-To-Rail,” ElectronicDesign, Feb. 17, 1997, p. 87.[9] Motorola Application Note AN1646, 1998, Phoenix, Sensor Device Data/Handbook,DL200/D Rev. 4, 1998.[10] Swager, A. W., “Evolving ADCs Demand More From Amplifiers,” Electronic DesignNews, Sept. 29, 1994, pp. 53–62.