A 4-channel ASIC for X-ray CCD readout based on incremental sigma delta ADC

A four-channel Application Specific Integrated Circuit (ASIC) is proposed to read out Charge Coupled Device (CCD) used for X-ray detection. Each channel, which consists of two incremental sigma delta (ΣΔ) Analog-to-Digital Converters (ADCs), can process the input signals in parallel. To reduce the mismatch between different channels, a digital calibration module is added. The prototype is implemented in 0.35pm CMOS technology. Measurement results show this ASIC exhibits 0.064% Integrated Non-Linearity (INL) throughout its input dynamic range of 0~20mV with 24.6μV equivalent input noise.