A novel compact topology for high-resolution CMOS/BiCMOS spectroscopy amplifiers

In this work, we present the extensive analysis of a new class of current-mode shaping amplifiers that can be realized in CMOS or BiCMOS technology. They are suitable for high-resolution spectroscopy, as we have demonstrated in previous works. The proposed topology is suitable to design shaping amplifiers with a wide range of time constants (∼0.1-10 μs) in a very compact scheme. In particular, we show the results of two fourth-order shapers characterized by 500- and 167-ns shaping time, respectively, realized in 0.8-μm BiCMOS technology. The two prototypes were designed in view of the use with Silicon Drift Detectors for X-ray spectroscopy applications. The measured integral nonlinearity is below ±0.1% and the achieved energy resolution at the Mn Kα line (measured with the proposed spectroscopy amplifier with a 5 mm² Peltier-cooled Silicon Drift Detector) is 160 eV full width at half maximum (FWHM) with 500-ns shaping time, comparable to the one obtained with a commercial shaping amplifier with the same time constant.