【Device Papers】A Pixel-to-Column Digital Readout Circuit with InPixel CDS for Ga₂O₃ UV Photodetectors

      Researchers from the Shandong Technology and Business University have published a dissertation titled "A Pixel-to-Column Digital Readout Circuit with InPixel CDS for Ga₂O₃ UV Photodetectors" in 2025 10th International Conference on Integrated Circuits and Microsystems (ICICM).

Abstract

      This paper presents a pixel-to-column digital readout circuit for Ga₂O₃ UV Photodetectors. The readout circuit includes a pixel-level input circuit, a column-level programmable gain amplifier (PGA) with single-ended to differential conversion, and an analog-to-digital converter (ADC). The pixel-level input circuit adopts a capacitive trans-impedance amplifier (CTIA) and incorporates correlated double sampling (CDS) technology to effectively reduce reset noise and other low-frequency noise. The single-ended to differential PGA is employed to amplify the signal and convert the input-stage single-ended signal into a differential signal suitable for the subsequent ADC input. The ADC adopts an incremental delta-sigma ADC (IADC) architecture, in which the IADC modulator is integrated within the readout circuit, while the digital filter is implemented off-chip. The proposed readout circuit is implemented in a standard TSMC 180 nm CMOS process. The simulation results indicate that within the proposed readout circuit, the pixel-level input stage achieves 99.99% linearity at a 1.8 V output swing. Following CDS processing, the output reset noise is reduced to 625μV. Additionally, the implemented IADC supports 14-bit digital signal conversion.

DOI：

https://doi.org/10.1109/ICICM66614.2025.11316039