Development of waveform multiplexing CMOS ASIC with decay time modulation for pixellated detectors

A novel waveform multiplexing method has been proposed to implement mixed-signal design in large multichannel front-end electronics systems. By multiplexing analog channels with decay time modulation, this new approach is able to increase readout channels without increasing the number of analog to digital converters and digital circuits. Therefore, the die area usage and power consumption per-channel could be greatly reduced. With 2-to-1 waveform multiplexing implementation, a 36-channel multiplexing preamplifier ASIC chip and a 24-channel multiplexing waveform sampling ASIC chip have been designed and fabricated with Rohm 0.35 μm CMOS process. For the 36-channel ASIC, the multiplexed preamplifiers have been tested to have an optimum ENC of about 2600 e- FWHM, which degrades from 1000 e- FWHM ENC of original preamplifier component. The 24-channel ASIC has successfully digitized waveforms from multiplexed channels with different decay time.