A 0.8 mu m CMOS pixel IC for low energy X-ray spectroscopy with on-chip detector

A charge sensitive readout chain has been developed For pixel applications with small die area and low power dissipation. The overall measured gain is 500mV/fC; the ENC is 15.3e(-) rms@15fF; the power dissipation is 1.5mW@3.3 V with 30pF load capacitance; the active die area is 270 mu mx270 mu m. A d etector has been integrated on the same substrate with the electronics. It consists of a 20 mu mx20 mu m diode, which is DC coupled to the input of th e readout chain. The IC has been designed and fabricated in a 0.8 mu m comm ercially available CMOS technology. A series of tests has been performed em ploying X-ray sources with energies from 2.3 to 3.3keV. The experimental re sults are reported and the noise characteristics of the system are evaluate d. With a FWHM of less than 300eV in room temperature, low energy X-ray spe ctroscopy is clearly feasible using an integrated detector element in comme rcial CMOS technology.