ABSTRACT
Complementary metal–oxide–semiconductor (CMOS) technologies have fully proven their adequacy for implementing data acquisition architectures based on functional blocks such as charge preamplifiers, sample and hold amplifiers, analog-to-digital converters, in analog signal processing for particle physics, nuclear physics, and x- or beta-ray detection. In CMOS technology two major noise sources exist: thermal noise and flicker noise. In contrast to channel thermal noise, which is well understood, the flicker noise mechanism is more complex, although its presence is surprisingly universal in all types of semiconductor devices. The Charge-Sensitive Amplifier (CSA) is commonly implemented using a folded cascode structure, built of transistors M1, M2, and M4. This architecture provides a high direct current gain and a relatively large operating bandwidth. It is obvious that CSA input noise is in practice defined by the detector capacitance, the peaking time specification, and the selection of the input MOS type and dimensions.
