Low-noise fast charge sensitive amplifier with dynamic signal compression

This work is concerned with the experimental characterization of a Charge Sensitive Amplifier featuring dynamic signal compression, fast recovery time, low noise and reduced area occupancy. The device takes advantage of the non-linear features of an inversion-mode MOS capacitor to fit a wide input dynamic range into the available output swing. It can be operated in synchronous mode at high frame rates, of the order of few MHz, thanks to a wide bandwidth, an improved output stage and a fast reset network. The reduced area occupancy makes the amplifier suitable for integration in a 100x 100 μm2 pixel area. All these features make the device a good candidate for applications where a fast front-end with a non-linear response is required, such as in imaging instrumentation for Free Electron Laser experiments. The aim of the paper is to show the experimental results coming from the characterization of the first prototype of the circuit which has been designed in a 65 nm CMOS technology. within the PixFEL Project funded by the INFN, Italy.