{"title":"A Low-Power Fully Dynamic Latched Comparator Using Flexible Oxide TFT Technology","authors":"Vaishali Choudhary;Pydi Ganga Bahubalindruni","doi":"10.1109/LSSC.2025.3557862","DOIUrl":"https://doi.org/10.1109/LSSC.2025.3557862","url":null,"abstract":"This letter presents a novel low-power, fully dynamic, latched comparator using only n-type, single-gate amorphous-indium-gallium-zinc-oxide thin-film transistors (a-IGZO TFTs) on a <inline-formula> <tex-math>$27~mu $ </tex-math></inline-formula>m thick polyimide substrate. This circuit demonstrates a stable performance up to an input signal frequency of 15 kHz with 1-MHz clock. By employing a pseudo-CMOS bootstrapped load, it achieved an output voltage swing of around 90%, an input-referred offset and noise voltages of 28 mV and 14 mV, respectively from measurements. In addition, it can reliably detect a minimum differential input voltage of 50 mV at a <inline-formula> <tex-math>$V_{mathrm { DD}}$ </tex-math></inline-formula> of 4 V, while consuming only <inline-formula> <tex-math>$8~mu $ </tex-math></inline-formula>W power. Therefore, this design is well-suited in biomedical wearable devices which typically needs low-power.","PeriodicalId":13032,"journal":{"name":"IEEE Solid-State Circuits Letters","volume":"8 ","pages":"101-104"},"PeriodicalIF":2.2,"publicationDate":"2025-04-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143850040","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Analysis of Power Consumption and Propagation Delay in Voltage Level Shifters","authors":"Mehdi Saberi;Alexandre Schmid","doi":"10.1109/LSSC.2025.3557524","DOIUrl":"https://doi.org/10.1109/LSSC.2025.3557524","url":null,"abstract":"The analysis of the operation of nonlinear circuits, such as voltage level shifters and latched comparators, and therefore the prediction of their propagation delay and power consumption, is challenging. This is because the operating points of the employed nonlinear devices are time-varying. Hence, in this letter, a new approach which uses the trajectory of the operating points of the employed devices is proposed to analyze nonlinear circuits. The proposed method is used to provide a comprehensive study about the operation of the cross-coupled voltage level shifters. The proposed analysis not only formulates the existing contention between the pull-up and pull-down devices but also presents closed-form formulas for the delay as well as the power consumption. Measurement results of a prototype implemented in a standard 0.18-<inline-formula> <tex-math>$mu $ </tex-math></inline-formula>m CMOS technology verify the effectiveness of the proposed method.","PeriodicalId":13032,"journal":{"name":"IEEE Solid-State Circuits Letters","volume":"8 ","pages":"113-116"},"PeriodicalIF":2.2,"publicationDate":"2025-04-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143871027","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Guangxu Shen;Haitao Ma;Chenyang Zhang;Dingyuan Zeng Member;Haoshen Zhu;Wenquan Che
{"title":"GaN HEMT-Based Resonators Using Parasitic Effects and Its Application to A Ka-band Coupled-Resonator SPDT Switch","authors":"Guangxu Shen;Haitao Ma;Chenyang Zhang;Dingyuan Zeng Member;Haoshen Zhu;Wenquan Che","doi":"10.1109/LSSC.2025.3557531","DOIUrl":"https://doi.org/10.1109/LSSC.2025.3557531","url":null,"abstract":"A series of switchable resonators are proposed by incorporating the parasitic effects of two gallium nitride (GaN) high electron mobility transistor (HEMT) devices in this letter, based on which a broadband single-pole double-throw (SPDT) switch is presented with a bandpass response. As for on-chip switches, the ideal transistor is desired to act as a capacitor in its off-state but a resistor in its on-state. In conventional switch designs, the inductive effects of transistors are typically suppressed due to their detrimental impact on impedance matching and isolation. In contrast to this conventional approach, this study proposes a resonator-based design strategy that intentionally exploits and amplifies these inductive characteristics to construct two distinct GaN HEMT-integrated resonators. The first resonator employs the enhanced on-state inductance of a switching transistor combined with an MIM capacitor to form a series resonant network, enabling broadband impedance matching. The second resonator utilizes the large off-state capacitance of a power transistor and a short-circuited transmission line to establish a parallel resonant network. Leveraging the unique properties of these resonators, a broadband switch topology is accordingly proposed and experimentally validated. For demonstration, a SPDT switch is designed and fabricated in a 100 nm GaN-on-Si process. The proposed switch operates from 16 to 33 GHz based on experimental measurements. Two transmission poles are observed in the passband. This result experimentally validates the GaN HEMT-based resonator design.","PeriodicalId":13032,"journal":{"name":"IEEE Solid-State Circuits Letters","volume":"8 ","pages":"105-108"},"PeriodicalIF":2.2,"publicationDate":"2025-04-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143850828","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"A 4×56 -Gbaud PAM-4 Linear and Low-Noise TIA for Linear-Drive Pluggable Optics","authors":"Wei Chen;Minhao Li;Ming Zhong;Yuan Li;Ying Wu;Pisen Zhou;Patrick Yin Chiang","doi":"10.1109/LSSC.2025.3574875","DOIUrl":"https://doi.org/10.1109/LSSC.2025.3574875","url":null,"abstract":"This letter presents a <inline-formula> <tex-math>$4times 56$ </tex-math></inline-formula>-Gbaud linear transimpedance amplifier (TIA) with low noise and high linearity, designed for linear-drive pluggable optics (LPO) and implemented in 0.13-<inline-formula> <tex-math>$mu $ </tex-math></inline-formula>m SiGe-BiCMOS technology (fT/f<inline-formula> <tex-math>${_{text {MAX}}} {=} 260$ </tex-math></inline-formula>/350 GHz). The TIA features an inductive shunt-feedback (ISFB) transimpedance stage (TIS) with a <inline-formula> <tex-math>$pi $ </tex-math></inline-formula>-topology L-C network as the input stage, achieving wide bandwidth (BW) and low noise despite large photodiode (PD) and packaging parasitic capacitances. Two current-splitting variable gain amplifiers (VGAs) with continuous-time linear equalizer (CTLE) functionality are cascaded after the TIS, providing a gain control range of –12 to +18 dB and accommodating input currents up to 2mApp. A 50-ohm output buffer with T-coil further extends the BW. Measurement results demonstrate a maximum optical-to-electrical transimpedance gain (O/E.ZT) of 73.8 dB<inline-formula> <tex-math>$Omega $ </tex-math></inline-formula>, an O/E O/E.BW exceeding 40 GHz, an input-referred noise (IRN) current of <inline-formula> <tex-math>$1.9~mu $ </tex-math></inline-formula>Arms, and total harmonic distortion (THD) ¡ 4.5% for a 700-mVpp output swing. The TIA supports 56-Gbaud PAM-4 eye diagrams with PRBS31Q and achieves 9.7-dBm optical modulation amplitude (OMA) sensitivity at the pre-FEC BER limit of <inline-formula> <tex-math>$2.4times 10^{-4}$ </tex-math></inline-formula> for 56-Gbaud PAM-4 SSPRQ. The design achieves a power efficiency of 1.67 pJ/bit and occupies an area of <inline-formula> <tex-math>$3.14times 1.04$ </tex-math></inline-formula> mm2.","PeriodicalId":13032,"journal":{"name":"IEEE Solid-State Circuits Letters","volume":"8 ","pages":"197-200"},"PeriodicalIF":2.2,"publicationDate":"2025-03-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144663709","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"A 302.5-GHz 30.9-dB-Gain THz Amplifier in 65-nm CMOS","authors":"Yu-Kai Chen;Yi-Fan Tseng;Wei-Zhe Su;Chun-Hsing Li","doi":"10.1109/LSSC.2025.3574413","DOIUrl":"https://doi.org/10.1109/LSSC.2025.3574413","url":null,"abstract":"A 302.5-GHz high-gain CMOS THz amplifier is proposed in this work. An electromagnetic (EM) modeling approach, verified by transistor measurements, is employed to optimize transistor layout, effectively reducing gate resistance and drain-to-gate capacitance. This significantly enhances the transistor’s maximum oscillation frequency <inline-formula> <tex-math>$f_{mathrm {max }}$ </tex-math></inline-formula> from 239.7 to 367.5 GHz. Furthermore, a <inline-formula> <tex-math>$G_{mathrm {max }}$ </tex-math></inline-formula>-peak-offset-matching technique is proposed to simultaneously optimize active transistors and passive matching networks, significantly increasing the gain by 3.5 dB. Implemented in a 65-nm CMOS technology, the proposed THz amplifier achieves a measured gain of 30.9 dB at 302.5 GHz with an output saturation power of –5.3 dBm while only consuming 35.4 mW from a 1.1 V supply. To the best of the authors’ knowledge, this work exhibits the first experimental validation of the EM modeling approach and achieves the highest reported gain above 200 GHz in bulk CMOS technologies.","PeriodicalId":13032,"journal":{"name":"IEEE Solid-State Circuits Letters","volume":"8 ","pages":"165-168"},"PeriodicalIF":2.2,"publicationDate":"2025-03-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144331799","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Secure FMCW LiDAR Ranging With an Electro-Optical Synthesizer at 5000 Measurements/s","authors":"Marziyeh Rezaei;Liban Hussein;Alana Dee;Shucheng Fang;Qixuan Lin;Mo Li;Sajjad Moazeni","doi":"10.1109/LSSC.2025.3555948","DOIUrl":"https://doi.org/10.1109/LSSC.2025.3555948","url":null,"abstract":"Frequency-modulated continuous wave (FMCW) LiDAR offers a significant advantage over FMCW RADAR due to its superior lateral resolution, achieving more than a <inline-formula> <tex-math>$1000times $ </tex-math></inline-formula> improvement. However, laser nonlinearities require the use of electro-optical phase-locked loops (EO PLLs), and conventional EO PLL-based FMCW LiDAR systems are susceptible to spoofing attacks. To address this vulnerability, this letter introduces an electro-optical (EO) synthesizer designed to generate FMCW signals with randomly varying chirp rates per frame. The synthesizer incorporates an on-chip SRAM-based physically unclonable function (PUF) fabricated in 180-nm RF CMOS, which generates a device-specific random key to enhance the security of FMCW LiDAR against spoofing attacks. The synthesizer supports four programmable chirp rates: from 8.5 to 12 GHz/ms with a chirp period of <inline-formula> <tex-math>$600~mu $ </tex-math></inline-formula>s, and from 12.75 to 18 GHz/ms with a chirp period of <inline-formula> <tex-math>$200~mu $ </tex-math></inline-formula>s, resulting in a <inline-formula> <tex-math>$5times $ </tex-math></inline-formula> increase in generated cloud points compared to existing long-range EO PLL-based FMCW LiDAR systems.","PeriodicalId":13032,"journal":{"name":"IEEE Solid-State Circuits Letters","volume":"8 ","pages":"93-96"},"PeriodicalIF":2.2,"publicationDate":"2025-03-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143830476","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Two 7–13-GHz GaAs-SiGe Four–Channel Beamforming Chiplets With/Without Metallic Interlayer Shields","authors":"Nengxu Zhu;Yiting Zhang;Genyin Ma;Fanyi Meng","doi":"10.1109/LSSC.2025.3573757","DOIUrl":"https://doi.org/10.1109/LSSC.2025.3573757","url":null,"abstract":"This letter presents two 7–13-GHz GaAs-SiGe four-channel beamforming chiplets to minimize the chip area. The chips integrate GaAs-based power amplifiers (PAs) and low-noise amplifiers (LNAs) with silicon-based phase and amplitude control modules using gold bumps. To mitigate coupling between the metal patterns of the heterogeneous chips and avoid interference with beamforming performance, a metallic interlayer shield is introduced at the interface. This shield ensures effective integration and preserves the functionality and performance of both the compound and silicon-based components. The fabricated four-channel 3-D heterogeneous integrated radio-frequency front-end chips, using 0.25-<inline-formula> <tex-math>$mu $ </tex-math></inline-formula>m GaAs and 0.13-<inline-formula> <tex-math>$mu $ </tex-math></inline-formula>m SiGe BiCMOS processes, achieve 6-bit amplitude/phase control with 0.5 dB/5.625° resolution with power consumption of 3.6 W (TX) and 1.6 W (RX). The RMS amplitude and phase errors are <0.6> <tex-math>$mathrm { OP_{1dB}}$ </tex-math></inline-formula> and −1.5-dBm RX IP1dB, with a compact total area of <inline-formula> <tex-math>$4.1times 3.05$ </tex-math></inline-formula> mm2.","PeriodicalId":13032,"journal":{"name":"IEEE Solid-State Circuits Letters","volume":"8 ","pages":"161-164"},"PeriodicalIF":2.2,"publicationDate":"2025-03-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144272698","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"A 24 V-to-1 V Low Input Current Ripple SC Hybrid Converter With Conducted EMI Noise Precompensation Filter and Current-Modulated Gate-Driver for Automobile Application","authors":"Yu-Tse Shih;Li-Jen Huang;Xiao-Quan Wu;Wei-Chieh Hung;Tz-Han Hsu;Kuo-Lin Zheng;Ke-Horng Chen;Ying-Hsi Lin;Shian-Ru Lin;Tsung-Yen Tsai","doi":"10.1109/LSSC.2025.3554811","DOIUrl":"https://doi.org/10.1109/LSSC.2025.3554811","url":null,"abstract":"The proposed low input current ripple (LICR) switched-capacitor (SC) hybrid converter effectively minimizes input current ripple by incorporating a precompensation active biasing electromagnetic interference (EMI) filter (PABEF), addressing EMI issues in automotive applications without requiring large external components. In addition, the current-modulation gate driver (CMGD) helps suppress conducted EMI noise at high frequencies. As a result, the LICR achieves a 74% reduction in input current ripple, EMI noise attenuation of 32 dB at low frequencies and 5 dB at high frequencies, and a peak efficiency of 93.3% at <inline-formula> <tex-math>$V_{mathrm { O}}$ </tex-math></inline-formula>/<inline-formula> <tex-math>$V_{mathrm { IN}}{=}1.8$ </tex-math></inline-formula>/24.","PeriodicalId":13032,"journal":{"name":"IEEE Solid-State Circuits Letters","volume":"8 ","pages":"89-92"},"PeriodicalIF":2.2,"publicationDate":"2025-03-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143821616","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Kedar Bhatt;Stafford Hutchins;Atresh Sanne;Mohammad M. Hasan;Zhanping Chen;Jaydeep P. Kulkarni
{"title":"A Bandgap Diode-Based Voltage Band Detection Circuit With Fast Response Time and Low Vmin on Intel 4 Logic Technology","authors":"Kedar Bhatt;Stafford Hutchins;Atresh Sanne;Mohammad M. Hasan;Zhanping Chen;Jaydeep P. Kulkarni","doi":"10.1109/LSSC.2025.3572385","DOIUrl":"https://doi.org/10.1109/LSSC.2025.3572385","url":null,"abstract":"A fast, accurate, single-rail voltage detection circuit (VDC) is presented. Low voltage operation is achieved by a variable gain Charge Pump (CP) followed by a Low-Dropout regulator (LDO). An Open-loop band gap reference (BGREF), passed to a dynamic comparator, achieves an undervoltage trip point of 0.62 V with 8.7 mV sigma, and an overvoltage trip point of 1.22 V with 12 mV sigma, demonstrated on Intel 4 silicon prototype. The design operates without any filter cap, allowing a fast, power-on ramp of <inline-formula> <tex-math>$2~mu $ </tex-math></inline-formula>s, and brown-out detection of <200 ns. A voltage band detection of 0.48–1.22 V is enabled through a finite-state machine (FSM) to modify CP and LDO gain depending on input voltage.","PeriodicalId":13032,"journal":{"name":"IEEE Solid-State Circuits Letters","volume":"8 ","pages":"157-160"},"PeriodicalIF":2.2,"publicationDate":"2025-03-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144243872","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Zehang Wu;Chi-Hang Chan;Yan Zhu;Rui P. Martins;Minglei Zhang
{"title":"An Inverter-Based Sampling Front-End Achieving >46-dB SFDR at 50-GHz Input","authors":"Zehang Wu;Chi-Hang Chan;Yan Zhu;Rui P. Martins;Minglei Zhang","doi":"10.1109/LSSC.2025.3552520","DOIUrl":"https://doi.org/10.1109/LSSC.2025.3552520","url":null,"abstract":"This letter presents a 32-GS/s per-way hierarchical sampling front-end (SFE) for time-interleaved ADCs, featuring both high linearity and energy efficiency with inherent embedded gain from an inverter-based topology. The P/N ratio configuration extends its applicable input common-mode voltage range. Both active and passive extensions improve the bandwidth of the SFE supplied by a core-device voltage. Furthermore, an improved dual-path bootstrapped switch enhances the sampling bandwidth and linearity at 8 GS/s. Fabricated in a 28-nm CMOS process, the inverter-based SFE achieves 30-GHz bandwidth while consuming 49.4 mW from a 0.95-V supply. The measured spurious free dynamic range (SFDR) and signal-to-noise and -distortion ratio (SNDR) at 50-GHz input are 46.9 dB and 36.1 dB, respectively.","PeriodicalId":13032,"journal":{"name":"IEEE Solid-State Circuits Letters","volume":"8 ","pages":"81-84"},"PeriodicalIF":2.2,"publicationDate":"2025-03-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143761314","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}