Shaper Design in CMOS for High Dynamic Range

Front-end electronics for capacitive sensors typically include a preamplifier followed by a filter. The preamplifier provides low-noise amplification of the signals induced in the sensor electrodes. The filter, by properly limiting the signal bandwidth, maximizes the Signal-to-Noise (S/N) ratio. Additionally, the filter limits the duration of the output signal associated with the measured event and, for those sensors where the induced signal is relatively slow, it maximizes the signal amplitude.