A VERY LOW-NOISE CMOS PREAMPLIFIER FOR CAPACITIVE SENSORS

A CMOS preamplifier optimized for piezoelectric transducers is presented. The extensive use of CMOS-compatible lateral bipolar transistors (CLBT's) and careful layout leads to a very low noise along with good untrimmed dc and ac characteristics. These features make it competitive with bipolar and JFET realizations. In addition, long coaxial lines can be driven without significant alteration of performance using the two uncommitted on-chip buffers. This circuit was fabricated in a standard 3-mum p-well CMOS technology, opening perspectives to monolithic integration of data acquisition subsystems.