Development of a low-noise analog front-end ASIC for CdTe detectors

This paper describes the recent development of a low-noise analog front-end ASIC for CdTe detectors. The ASIC is designed on the basis of the Open-IP LSI project led by JAXA and implemented using TSMC 0.35-mu m CMOS technology. The ASIC contains eight identical channels, each of which includes a charge-sensitive amplifier, band-pass filters, and a sample-and-hold circuit. Preliminary testing of the ASIC achieved noise performance of 188e(-) + 7.5e(-)/pF. In order to verify the low-noise characteristics, the ASIC was connected to a guard-ring-equipped CdTe diode detector with dimensions of 2.4 x 2.4 mm and having a thickness of 0.5 mm. As a result, the gamma-ray spectra of radioactive sources were obtained with good energy resolutions of 2.51 and 2.35 keV (FWHM) for gamma rays of 59.5 and 122 keV, respectively, at room temperature. (C) 2007 Elsevier B.V. All rights reserved.