Design and performance of 0.18-μm CMOS charge preamplifiers for APD-based PET scanners

The CMOS 0.18-μm technology was investigated for two analog front-end projects: the low-power budget rat-head mounted miniature rat conscious animal PET (RatCAP) scanner, and the high-performance, low-noise, high-rate PET/CT application. The first VLSI prototypes consisted of 1- and 5-mW charge sensitive preamplifiers (CSP) based on a modified cascode telescopic architecture. Characterization of the rise time, linearity, dynamic range, equivalent noise charge (ENC), timing resolution and energy resolution are reported and discussed. When connected to an APD-LSO detector, time resolutions of 2.49 and 1.56 ns full-width half-maximum (FWHM) were achieved by the 1- and 5-mW CSPs, respectively. Both CSPs make it possible to achieve performance characteristics that are adequate for PET imaging. Experimental results indicate that the CMOS 0.18-μm technology is suitable for both the low-power and the high-performance PET front-end applications.