{"title":"A Multi-Stage RC Compensation Technique for Decoupling the Transimpedance and BW: Creating High Speed and Low Noise TIA Designs","authors":"Muhammad Bilal Babar;Gordon W. Roberts","doi":"10.1109/TCSI.2025.3556802","DOIUrl":null,"url":null,"abstract":"The gain and bandwidth of a shunt-feedback Transimpedance Amplifier (TIA) is limited by a so called transimpedance (TI) limit. This limit dictates the maximum possible value of the feedback resistance (<inline-formula> <tex-math>$R_{F}$ </tex-math></inline-formula>) for a targeted bandwidth. Additionally, the input referred noise of such TIAs is inversely proportional to the <inline-formula> <tex-math>$R_{F}$ </tex-math></inline-formula>, which presents a challenge in simultaneous optimization of bandwidth, noise and transimpedance gain. In this paper, the TI limit is revisited, and a multi-stage RC compensation technique is presented for the design of the open-loop amplifier for a closed-loop shunt-feedback-based TI stage. This paper shows that with the appropriate pole-zero positioning, the DC transimpedance gain can be decoupled from the closed-loop TI bandwidth. This is achieved by placing a zero in the open loop transfer function to reduce the impact of the closed loop dominant pole created by the input capacitance and the RF. As a result, without the need for area consuming inductors, a TI stage is realized which has a transimpedance limit that is larger than the conventionally assumed limit. Additionally, the proposed RC compensation network provides more control over the pole-zero positioning which results in smooth overall frequency response after equalization. This is verified by experimental results which show that the proposed technique achieves a much greater transimpedance gain as compared to that of the conventional limit while reducing the noise and without any significant deterioration of bandwidth. The design has been implemented in a 90 nm BiCMOS process from Global Foundries (GF-9HP). A detailed comparison of the proposed approach is presented with other TIA designs. As per the author’s best knowledge, the proposed design outperforms the state-of-the-art TIA designs in terms of the noise-transimpedance-bandwidth trade-off.","PeriodicalId":13039,"journal":{"name":"IEEE Transactions on Circuits and Systems I: Regular Papers","volume":"72 8","pages":"3847-3860"},"PeriodicalIF":5.2000,"publicationDate":"2025-04-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=10962192","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"IEEE Transactions on Circuits and Systems I: Regular Papers","FirstCategoryId":"5","ListUrlMain":"https://ieeexplore.ieee.org/document/10962192/","RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q1","JCRName":"ENGINEERING, ELECTRICAL & ELECTRONIC","Score":null,"Total":0}
引用次数: 0
Abstract
The gain and bandwidth of a shunt-feedback Transimpedance Amplifier (TIA) is limited by a so called transimpedance (TI) limit. This limit dictates the maximum possible value of the feedback resistance ($R_{F}$ ) for a targeted bandwidth. Additionally, the input referred noise of such TIAs is inversely proportional to the $R_{F}$ , which presents a challenge in simultaneous optimization of bandwidth, noise and transimpedance gain. In this paper, the TI limit is revisited, and a multi-stage RC compensation technique is presented for the design of the open-loop amplifier for a closed-loop shunt-feedback-based TI stage. This paper shows that with the appropriate pole-zero positioning, the DC transimpedance gain can be decoupled from the closed-loop TI bandwidth. This is achieved by placing a zero in the open loop transfer function to reduce the impact of the closed loop dominant pole created by the input capacitance and the RF. As a result, without the need for area consuming inductors, a TI stage is realized which has a transimpedance limit that is larger than the conventionally assumed limit. Additionally, the proposed RC compensation network provides more control over the pole-zero positioning which results in smooth overall frequency response after equalization. This is verified by experimental results which show that the proposed technique achieves a much greater transimpedance gain as compared to that of the conventional limit while reducing the noise and without any significant deterioration of bandwidth. The design has been implemented in a 90 nm BiCMOS process from Global Foundries (GF-9HP). A detailed comparison of the proposed approach is presented with other TIA designs. As per the author’s best knowledge, the proposed design outperforms the state-of-the-art TIA designs in terms of the noise-transimpedance-bandwidth trade-off.
期刊介绍:
TCAS I publishes regular papers in the field specified by the theory, analysis, design, and practical implementations of circuits, and the application of circuit techniques to systems and to signal processing. Included is the whole spectrum from basic scientific theory to industrial applications. The field of interest covered includes: - Circuits: Analog, Digital and Mixed Signal Circuits and Systems - Nonlinear Circuits and Systems, Integrated Sensors, MEMS and Systems on Chip, Nanoscale Circuits and Systems, Optoelectronic - Circuits and Systems, Power Electronics and Systems - Software for Analog-and-Logic Circuits and Systems - Control aspects of Circuits and Systems.