Akademik Veri Yönetim Sistemi
IEEE Transactions on Circuits and Systems I: Regular Papers, cilt.73, sa.4, ss.2464-2473, 2026 (SCI-Expanded, Scopus)
Substantial parasitic data-line capacitance Cp in thin-film-transistor-based active-matrix flat-panel X-ray imagers limits the noise performance, bandwidth, and linearity of the analog front-end (AFE) integrated circuit, normally comprised of a charge-sensitive amplifier (CSA) to process pC-level input signals, followed by a lowpass filter. To mitigate the adverse effect of Cp on noise, we develop and implement, for the first time for X-ray-imager AFEs, two techniques based on introducing a low-noise auxiliary amplifier (AUX) to the AFE that improves noise performance without a significant increase in power consumption. In the first technique, we design the AUX to introduce a negative capacitance that neutralizes Cp. In the second, we design the AUX to provide a feedforward path around the CSA that cancels the CSA noise. In both approaches, the AUX determines the overall AFE noise performance, allowing the CSA to be designed to meet relaxed bandwidth, gain error, and linearity specifications. To demonstrate the performance of our proposed noise-reduction techniques, we present our design and experimental characterization of a single-channel AFE in a 1.8-V-supply 180-nm mixed-signal CMOS technology. Experimental results from our prototype chip indicate that both methods provide at least 2:2 reduction in input-referred noise at the cost of no more than a 29% increase in static-power consumption compared to a conventional AFE.