A CMOS readout amplifier for instrumentation applications

An integrated readout amplifier for instrumentation applications in smart sensor systems is presented. A fully integrated CMOS version of such an amplifier has been developed using switched-capacitor techniques. The amplifier system provides differential input capability, programmable amplification, clock generation, and low-pass filtering on the chip. The output signal is continuous in time and the system can be used without any of the special precautions necessary for sampled-data circuits. Emphasis was put on high PSRR (-63 dB at DC), low noise (10- mu V/sub rms/ input equivalent wideband noise) and offset, low harmonic distortion, and small amplification error (<0.06% at 4 V/sub pp/). To cover a large field of applications, only slightly different realizations can be used for capacitive sensors as well as for resistive sensor bridges.<
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