Measurement and data-assisted simulation of bit error rate in RQL circuits

A circuit-simulation-based method is used to determine the thermally-induced bit error rate of superconducting Single Flux Quantum logic circuits. Simulations are used to evaluate the multidimensional Gaussian integral across noise current sources attached to the active devices. The method is data-assisted and has predictive power. Measurement determines the value of a single parameter, effective noise bandwidth, for each error mechanism. The errors in the distributed networks of comparator-free Reciprocal Quantum Logic nucleate across multiple Josephson junctions, so the effective critical current is about three times that of the individual devices. The effective noise bandwidth is only 6%–23% of the junction plasma frequency at a modest clock rate of 3.4 GHz, which is 1% of the plasma frequency. This analysis shows the ways measured bit error rate comes out so much lower than simplistic estimates based on isolated devices.

A 4 GHz Single-to-Differential Cross-Coupled Variable-Gain Transimpedance Amplifier for Optical Communication

This letter presents an inductorless transimpedance amplifier (TIA) for visible light communication, using the UMC 40 nm CMOS process. It consists of a single-to-differential input stage with a modified cross-coupled regulated cascode design, followed by a modified fT-doubler mid-stage with a combined active inductor and capacitive degeneration design for bandwidth-enhancement and differential output. The mid-stage also has an attached common-mode feedback (CMFB) circuit. Both the input and mid-stages have gain-varying and peaking-varying functions. It has a measured gain range of 37.5–58.7 dBΩ and 4.15 GHz bandwidth using a 0.5 pF capacitive load. The gain range results in an input dynamic range of 33.2 µA–1.46 mA. Its input referred noise current is 10.7 pA/Hz, core DC power consumption is 7.84 mW from a VDDTIA of 1.6 V and core area is 39 µm × 26 µm.

Ultralow dark current in near-infrared perovskite photodiodes by reducing charge injection and interfacial charge generation

Metal halide perovskite photodiodes (PPDs) offer high responsivity and broad spectral sensitivity, making them attractive for low-cost visible and near-infrared sensing. A significant challenge in achieving high detectivity in PPDs is lowering the dark current density (JD) and noise current (in). This is commonly accomplished using charge-blocking layers to reduce charge injection. By analyzing the temperature dependence of JD for lead-tin based PPDs with different bandgaps and electron-blocking layers (EBL), we demonstrate that while EBLs eliminate electron injection, they facilitate undesired thermal charge generation at the EBL-perovskite interface. The interfacial energy offset between the EBL and the perovskite determines the magnitude and activation energy of JD. By increasing this offset we realized a PPD with ultralow JD and in of 5 × 10−8 mA cm−2 and 2 × 10−14 A Hz−1/2, respectively, and wavelength sensitivity up to 1050 nm, establishing a new design principle to maximize detectivity in perovskite photodiodes.

An Entropy-Based Anti-Noise Method for Reducing Ranging Error in Photon Counting Lidar

Photon counting lidar for long-range detection faces the problem of declining ranging performance caused by background noise. Current anti-noise methods are not robust enough in the case of weak signal and strong background noise, resulting in poor ranging error. In this work, based on the characteristics of the uncertainty of echo signal and noise in photon counting lidar, an entropy-based anti-noise method is proposed to reduce the ranging error under high background noise. Firstly, the photon counting entropy, which is considered as the feature to distinguish signal from noise, is defined to quantify the uncertainty of fluctuation among photon events responding to the Geiger mode avalanche photodiode. Then, the photon counting entropy is combined with a windowing operation to enhance the difference between signal and noise, so as to mitigate the effect of background noise and estimate the time of flight of the laser pulses. Simulation and experimental analysis show that the proposed method improves the anti-noise performance well, and experimental results demonstrate that the proposed method effectively mitigates the effect of background noise to reduce ranging error despite high background noise.

High Dynamic Range Photocurrent Sensory Circuit with a Multi-Transistor Background Light Cancellation Loop for Photoplethysmography Sensing

In this article, we present a new photocurrent sensory circuit with a three-transistor background light cancellation. We describe our innovative photocurrent sensor-based blood pressure measuring device using a resistor-based current-to-voltage converter with a background light cancellation (BLC) loop. The photocurrent sensor is implemented using 0.35 μm standard CMOS technology and has zero average power consumption. The post-layout simulation for the photocurrent sensor shows a 1.3 MΩ transimpedance gain, a referred input noise current of 11 pA, and can reject a DC photocurrent up to 200 μA. This high DC rejection has been achieved due to the newly proposed multi-transistor BLC loop integrated with the sensor.

Statistical Supervised Learning With Engineering Data: A Case Study of Low Frequency Noise Measured On Semiconductor Devices

Our practical motivation is the analysis of potential correlations between spectral noise current and threshold voltage from common on-wafer MOSFETs. The usual strategy leads to the use of standard techniques based on Normal linear regression easily accessible in all statistical software (both free or commercial). However, these statistical methods are not appropriate because the assumptions they lie on are not met. More sophisticated methods are required. A new strategy based on the most novel nonparametric techniques which are data-driven and thus free from questionable parametric assumptions is proposed. A backfitting algorithm accounting for random effects and nonparametric regression is designed and implemented. The nature of the correlation between threshold voltage and noise is examined by conducting a statistical test, which is based on a novel technique that summarizes in a color map all the relevant information of the data. The way the results are presented in the plot makes it easy for a non-expert in data analysis to understand what is underlying. The good performance of the method is proven through simulations and it is applied to a data case in a field where these modern statistical techniques are novel and result very efficient.

A Simulation Study of Noise Behavior in Basic Current Mirror using CNTFET and MOSFET

We present a aimulation study of noise behavior in basic current mirror using CNTFET and MOSFET, obtaining that the output noise current is always higher for the CNTFET than for the MOS device. Keywords— CNTFET, MOSFET, Modelling, Current Mirror Design, Advanced Design System (ADS).

Investigation of Low Frequency Noise-current Correlation for the InAs/GaSb T2SL Long-wavelength Infrared Detector

In this paper, a mesa-type 256×8 long-wavelength infrared detector is prepared by using InAs/GaSb type-II superlattice material with double barrieres structure. the area of each pixel is 25×25 μm2. The cut-off wavelength and dark current density of the detector at -0.05 V bias with liquid nitrogen temperature is 11.5 μm and 4.1×10-4 A/cm2, respectively. The power spectrum of low-frequency noise (1/f noise) at different temperatures have also been fitted by the Hooge model, and the correlations with dark current are extracted subsequently. The results shown that the 1/f noise of the detector is mainly caused by the generation-recombination current at a low reverse bias, however, when the reverse bias is high, the 1/f noise should be expressed by the sum of Igr noise and Ibtb noise which is ignored in the previous research. The 1/f noise-current correlation assessed in this work can provide insights into the low frequency noise characteristics of long-wavelength T2SL InAs/GaSb detectors, and allow for a better understanding of the main source of low-frequency noise.

A CMOS Optoelectronic Receiver IC with an On-Chip Avalanche Photodiode for Home-Monitoring LiDAR Sensors

This paper presents an optoelectronic receiver (Rx) IC with an on-chip avalanche photodiode (APD) realized in a 0.18-mm CMOS process for the applications of home-monitoring light detection and ranging (LiDAR) sensors, where the on-chip CMOS P+/N-well APD was implemented to avoid the unwanted signal distortion from bondwires and electro-static discharge (ESD) protection diodes. Various circuit techniques are exploited in this work, such as the feedforward transimpedance amplifier for high gain, and a limiting amplifier with negative impedance compensation for wide bandwidth. Measured results demonstrate 93.4-dBW transimpedance gain, 790-MHz bandwidth, 12-pA/√Hz noise current spectral density, 6.74-mApp minimum detectable signal that corresponds to the maximum detection range of 10 m, and 56.5-mW power dissipation from a 1.8-V supply. This optoelectronic Rx IC provides a potential for a low-cost low-power solution in the applications of home-monitoring LiDAR sensors.