A Low-Power Wilkinson-type ADC for CdZnTe Detectors in 0.13-μm CMOS

This paper presents the design of a low-power high-dynamic-range analog-to-digital converter (ADC) for solid-state radiation detectors, in particular Cadmium Zinc Telluride (CZT). The core of the ADC consists of a Wilkinson-type digitizer, a digital control unit and a 9-bit counter. The analog core of the ADC operates from a 3.3 V supply while the supply for the digital control circuitry is 1.2 V. The input dynamic range of the ADC is 2.7 V and the ADC consumes 631 mu W. The ADC is designed and laid-out in a standard 0.13-mu m CMOS process and occupies 0.026 mm(2). Post-layout simulation results show that the signal-to-noise and distortion ratio (SNDR) of the ADC is just over 50 dB which corresponds to an effective number of bits (ENOB) of approximately 8. The simulated differential and integral nonlinearities (DNL and INL) are +/- 0.065 LSB and 0.954 LSB, respectively.