IEEE sensors reviewsPub Date : 2025-01-01Epub Date: 2025-04-14DOI: 10.1109/sr.2025.3560917
Amr M Maghraby, Ibrahim Bozyel, Islam T Abougindia, Suat U Ay
{"title":"Review of In-Pixel Gain Amplifiers and Readout Circuits for Low-Light CMOS Image Sensors.","authors":"Amr M Maghraby, Ibrahim Bozyel, Islam T Abougindia, Suat U Ay","doi":"10.1109/sr.2025.3560917","DOIUrl":"10.1109/sr.2025.3560917","url":null,"abstract":"<p><p>The low-light performance of image sensors can be enhanced by designing high-effective conversion gain signal paths from photon conversion sites to chip outputs. This can be achieved by using high-gain in-pixel amplifiers, high-gain column amplifiers, and by reducing the conversion capacitance of photon-sensing nodes. However, each of these approaches presents unique challenges and limitations that have restricted their widespread adoption in low-light applications. This article reviews the use of in-pixel gain amplifiers and their signal chain electronics in high-conversion-gain complementary metal-oxide-semiconductor (CMOS) image sensors over the past two decades. In-pixel gain amplifiers are classified into different categories according to the type of amplification technique used. Analyses of the column-referred conversion gain and the noise of each topology are presented alongside the different metrics used to characterize CMOS image sensor pixels for low-light imaging applications. The performance metrics of various in-pixel gain amplifiers are compared, providing a framework that highlights the best achieved input-referred noise in CMOS image sensors over the past 15 years. Furthermore, different tradeoffs are examined between optimizing conversion gain, pixel full-well capacity, and input read noise in both voltage and charge domains.</p>","PeriodicalId":523896,"journal":{"name":"IEEE sensors reviews","volume":"2 ","pages":"95-111"},"PeriodicalIF":0.0,"publicationDate":"2025-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC13264286/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148255425","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}