ns公司的lmp8358是高精度可编增益仪表放大器，通过spi兼容的串口或并口可把增益编程为0,20,50,100,200,500,或1000，也可用两个外设电阻设定为任意值．单电源2.7v到5.5v工作，电流为1.8ma，增益zui大误差为0.15%，增益漂移为16ppm/℃，cmrr大于110db，失调电压小于10μv，失调电压漂移小于50nv/℃，增益带宽gbw（增益=10）8mhz，非线性小于100ppm，主要用在桥接传感器放大，热堆放大，手提仪表，医疗设备．本文主要介绍lmp8358主要特性，功能方框图，典型应用方框图，菊花和星形链接配置图以及差分桥接传感器应用电路图．
thelmp8358isaprecisionprogrammable-gaininstrumentationamplifierinnational’slmpprecisionamplifierfamily.itsgaincanbeprogrammedto10,20,50,100,200,500,or1000throughanspi-compatibleserialinterfaceorthroughaparallelinterface.alternatively,itsgaincanbesettoanarbitraryvalueusingtwoexternalresistors.thelmp8358usespatentedtechniquestomeasureandcontinuouslycorrectitsinputoffsetvoltage,eliminatingoffsetdriftovertimeandtemperatureandtheeffectof1/fnoise.itsground-sensingcmosinputfeaturesahighcmrrandlowinputbiascurrents.itiscapableofsensingdifferentialinputvoltagesinacommonmoderangethatextendsfrom100mvbelowthenegativesupplyto1.4vbelowthepositivesupply,makingitanidealsolutionforinterfacingwithground-referencedsensors,supply-referencedsensorbridges,andanyotherapplicationrequiringprecisionandlong-termstability.additionally,thelmp8358includesfaultdetectioncircuitrytodetectopenandshortedinputsanddeterioratingconnectionstothesignalsource.otherfeaturesthatmakethelmp8358aversatilesolutionformanyapplicationsareitsrail-to-railoutput,lowinputvoltagenoiseandhighgain-bandwidthproduct.
lmp8358主要特性：
typicalvaluesunlessotherwisenoted,ta=25℃
■supplyvoltage2.7vto5.5v
■supplycurrent1.8ma
■maxgainerror0.15%
■maxgaindrift16ppm/℃
■mincmrr110db
■maxoffsetvoltage10μv
■maxoffsetvoltagedrift50nv/℃
■gbw（gain=10）8mhz
■maxnon-linearity100ppm
■operatingtemperaturerange−40℃to125℃
■inputfaultdetection
■spiorpinconfigurablemodes
■emirrat1.8ghz92db
■14-pinsoicand14-pintssoppackage
lmp8358应用：
■bridgesensoramplifier
■thermopileamplifier
■portableinstrumentation
■medicalinstrumentation
■precisionlow-sidecurrentsensing
图１．lmp8358方框图
图２．lmp8358典型应用方框图
图３．lmp8358菊花链接配置图
图４．lmp8358每个寄存器不同写入值的星形链接配置图
图５．lmp8358差分桥接传感器应用电路图
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（本文转自电子工程世界：http://.cn/mndz/2011/0221/article_5044.html）