Minimum noise design of fast bipolar integrated amplifiers with low-power constraint

Bipolar devices are well suited for the extremely low-power circuits required in high-density multichannel detector systems. This work sets the rules for designing front-end bipolar integrated charge amplifiers with the minimum possible noise and a specific bandwidth, when the constraint of very low power dissipation is imposed. In particular, this paper analyses the role played by the bipolar parameters, such as the current gain and the base spreading resistance, as well as the effect on the noise performance due to the current gain dispersion and degradation. An optimum design condition is found and the consequences of a further reduction in dissipated power in the front-end stage is investigated.