A novel charge amplifying technique

A low-power, BiCMOS front-end amplifier for capacitive detector read-out is discussed. The QDCAL Amplifier is a combination of a Dynamically Controlled Active Load (DCAL) and a Charge (Q) Amplifier. The QDCAL has a gain of 25 mV/fC, a power consumption Pt of ≈ 1.15 mW (bias circuit not included), an output (0–100%) peaking time t(0–100%) of ≈ 8 ns at a detector capacitance Cdet = 21 pF, and a mid-band input referred series noise spectral density 〈en〉 and parallel noise spectral density 〈in〉 of ≈ 1.22 nV/√Hz and ≈ 1.26 pA/√Hz, respectively. The circuit was developed in the radiation hard SOI BiCMOS-PJFET technology of DMILL.