Resistive Feedback Research Articles

Wideband Input Matching CMOS Low-Noise Amplifier with Noise and Distortion Cancellation

In this paper, a wideband low-noise amplifier (LNA) is designed based on the resistive feedback topology with a TSMC 0.18[Formula: see text][Formula: see text]m standard RF CMOS process. Bandwidth expansion is provided by the second-order Chebyshev filter. The noise figure (NF) increases at high frequency because of the source parasitic capacitors of the cascode transistor; so, noise cancelling technique is applied to the cascode transistor of the proposed LNA. Bias conditions and sizes of the transistors are optimized to cancel the nonlinear transconductance ([Formula: see text]). With this modified technique, low noise figure, high linearity and improved input and output matching can be attained for 3.1–10.6[Formula: see text]GHz frequency band. Post-layout simulation result of the proposed LNA shows the maximum power gain of 17[Formula: see text]dB at 5.5[Formula: see text]GHz frequency, NF of lower than 4.5[Formula: see text]dB over the whole band of 3.1–10.6[Formula: see text]GHz, maximum IIP2 of [Formula: see text]28[Formula: see text]dBm and IIP3 of [Formula: see text]7.5[Formula: see text]dBm, while dissipating 9[Formula: see text]mW (with buffer) from a 1.8 V supply voltage. It occupies [Formula: see text]m silicon die area.

Low noise amplifier with resistive and capacitive feedback for 2.4 GHz RF receiver front end

Low noise amplifier with resistive and capacitive feedback for 2.4 GHz RF receiver front end

Targeting of the AXL receptor tyrosine kinase by small molecule inhibitor leads to AXL cell surface accumulation by impairing the ubiquitin-dependent receptor degradation

BackgroundOverexpression of AXL receptor tyrosine kinase (AXL) in various human cancers correlates with reduced patients overall survival and resistance to first line therapies. Therefore, several AXL tyrosine kinase inhibitors (TKIs) are currently under clinical evaluation.ResultsAXL TKI BMS777607 treatment increased AXL protein levels after 24 h as observed by Western blot and flow cytometry analysis. Mechanistically, this inhibition-induced AXL cell surface accumulation was neither associated with epigenetic modifications, nor altered transcriptional and translational regulation. Further, we saw no impact on glycosylation and receptor shedding by α-secretases. However, we observed that BMS777607 increased the glycosylated 140 kDa AXL protein abundance, which was impaired in the kinase dead mutant AXL (K567R). We demonstrated that AXL kinase activity and subsequent kinase phosphorylation is necessary for GAS6-dependent receptor internalization and degradation. Blocking of kinase function by BMS777607 resulted in ubiquitination prohibition, impaired internalization and subsequent cell surface accumulation. Subsequently, AXL cell surface accumulation was accompanied by increased proliferation of 3D-Speroids induced by low μM levels of BMS777607 treatment.ConclusionOur data suggest a re-evaluation of anti-AXL clinical protocols due to possible feedback loops and resistance formation to targeted AXL therapy. An alternative strategy to circumvent feedback loops for AXL targeting therapies may exist in linkage of AXL TKIs to a degradation machinery recruiting unit, as already demonstrated with PROTACs for EGFR, HER2, and c-Met. This might result in a sustained inhibition and depletion of the AXL from tumor cell surface and enhance the efficacy of targeted anti-AXL therapies in the clinic.

The Analysis of the Negative Feedback Circuit in the Induction Sensors

In this paper, the analysis method of the step response of the second-order system under different damping is applied to the feedback circuit analysis in the sensors. It analyzes the influence of different feedback resistors and mutual inductances on the system stability and pass band, which provides a theoretical basis for the matching of feedback resistors and mutual inductances in the circuit. It is of great significance to improve the performance of the sensor. when the parameters of the induction sensor are determined, the system performance can be more stable by designing appropriate mutual inductance and feedback resistance to make the damping ratio close to 0.8. Finally, we designed the feedback resistor Rf = 400 Ω, and the mutual inductance M = 1 to make sure damping ratio ζ be around 0.8 in the selected sensors.

E‐band power detector with robust temperature performance in 130 nm SiGe BiCMOS

This Letter presents an E-band power detector (PD) for robust operation throughout a wide temperature range. The PD is fabricated in a commercial 130 nm SiGe BiCMOS technology with f t / f max of 200/265 GHz. The relationship between responsivity of the PD and temperature was investigated. A set of target base bias voltages of the core heterojunction bipolar transistor (HBT) pair is deduced by simulating the PD circuit for an ideal constant responsivity over temperature. By means of fine control of the feedback resistor and HBT size of an improved current mirror, the bias voltages could be optimised to the target values. The measured detected RF power at 77 GHz exhibits <;0.75 dB variation across - 40 to + 85°C, which is one of the lowest variation PDs in the published works. The PD consumes 2.5 mW from a 2.5 V supply and the core area is only 220 μm × 130 μm.

915-MHz Continuous-Wave Doppler Radar Sensor for Detection of Vital Signs

A miniaturized continuous-wave Doppler radar sensor operating at 915 MHz to remotely detect both respiration and heart rate (beats per minute) is presented. The proposed radar sensor comprises a front-end module including an implemented complementary metal-oxide semiconductor low-noise amplifier (LNA) and fractal-slot patch antennas, whose area was reduced by 15.2%. The two-stage inverter-based LNA was designed with an interstage capacitor and a feedback resistor to acquire ultrawide bandwidth. Two operating frequencies, 915 MHz and 2.45 GHz, were analyzed with regard to path loss for efficient operation because frequency affects detection sensitivity, reflected signal power from the human body, and measurement distance in a far-field condition. Path-loss calculation based on the simplified layer model indicates that the reflected power of the 915 MHz radar could be higher than that of the 2.45 GHz radar. The implemented radar front-end module excluding the LNA occupies 35 × 55 mm2. Vital signs were obtained via a fast Fourier transform and digital filtering using raw signals. In an experiment with six subjects, the respiration and heart rate obtained at 0.8 m using the proposed radar sensor exhibited mean accuracies of 99.4% and 97.6% with respect to commercialized reference sensors, respectively.

A 2.6 ppm/°C 2.5 V Piece-Wise Compensated Bandgap Reference with Low Beta Bipolar

Traditional bandgap reference (BGR) is sensitive to process variation and is not suitable for mass production. Consequently, a stacked piece-wise compensated bandgap reference (SPWBGR) with low beta bipolar is proposed, designed and fabricated in the 0.18 μm high-voltage (HV) BCD process. Two stacked BGR (SBGR) cores make up the proposed BGR circuit. Through setting the target reference voltage near the output voltage of SBGR cores, the feedback resistor ratio is reduced and the base current side-effect is significantly decreased. Notably, the SBGR core is implemented by the low beta npn bipolar and it relaxes the requirement for the high beta bipolar. The two SBGR cores are almost identical except for the temperature slope and feedback ratio. The two cores have different zero temperature coefficient (TC) points, one is set at −5 °C, and the other is set at 60 °C, named as SBGRA and SBGRB, respectively. The SBGRA and SBGRB output the same voltage at their zero TC point. The higher voltage of SBGRA and SBGRB is the output voltage. Through the process of tracking the maximum value of different SBGR cores, the proposed SPWBGR achieves 2.6 ppm/°C TC from −40 to 100 °C. As a result, the average TC for five random samples is 5.3 ppm/°C. The line regulation is 2 mV/V from 4.5 to 5.5 V power supply. The current consumption is 6.8 µA. The active area of the proposed BGR is 0.075 mm2.

Effect of crab cavity high order modes on the coupled-bunch stability of High-Luminosity Large Hadron Collider

High frequency High Order Modes can significantly affect the coupled-bunch stability in a circular accelerator. With a large enough shunt impedance they may drive a coupled-bunch transverse instability. We have developed an analytical model and implemented it in the NHT Vlasov solver. The results show that the instability is characterized by the excitation of many azimuthal intra-bunch modes, which have similar growth rates, that make the traditional remedies such as a flat resistive feedback and chromaticity inefficient in suppressing it. For the High Luminosity Large Hadron Collider this could result in a significant increase of the stabilizing Landau octupole current, up to $\sim 100$ A ($\sim 20\%$ of the maximum available current). In order to limit the increase below 10 A ($\sim 2\%$), the transverse shunt impedance has to be kept below 1 M$\Omega$/m.

Sr Isotope Analysis of Picogram-Level Samples by Thermal Ionization Mass Spectrometry Using a Highly Sensitive Silicotungstic Acid Emitter.

Thermal ionization mass spectrometry (TIMS) has shown excellent analytical precision for Sr isotopic ratio analysis, even for small masses of material (0.5-10 ng). However, because of the sensitivity limit of TIMS, it is still not possible to obtain high precision 87Sr/86Sr isotope ratios for picogram-level sample sizes (30-100 pg) due to the lack of a highly sensitive emitter. This study is the first to employ a highly sensitive silicotungstic acid emitter to measure Sr isotopes at the picogram-level using TIMS. This emitter produces a 3-fold enhancement in the ionization efficiency of Sr and not only significantly reduces the required sample size but also has good external precision. Analyses of the NIST 987 standard yield an external reproducibility (2 RSD, n = 8) better than ±0.013% even for 30 pg of Sr. It is possible to yield an internal precision (2 RSE) of ±0.003% for 100 pg of sample using the default 1011 Ohm feedback resistors. This method was verified by using a suite of silicate reference materials. Replicate digestions and analyses ( n = 8) of the basalt standard BCR-2 (87Sr/86Sr = 0.704998 ± 0.000028, 2 SD) at the 326 ± 30 pg level demonstrates that good external reproducibility is reached on ultratrace level silicate samples. This method has a wide variety of potential applications for samples containing ultralow amounts of Sr in geoscience and archeological studies, such as single grains of mica, sphalerite, and pyrite, single mantle melt inclusions, precious extra-terrestrial materials, and human hair to name just a few.

A Wideband Blocker-Tolerant Receiver With Frequency-Translational Resistive Feedback

This paper presents a wideband frequency-translational resistive-feedback receiver (RX), operational from 0.1 to 2.2 GHz. Different blocker suppression techniques are proposed to improve both out-of-band (OOB) compression and weakly nonlinear distortion of the RX. The blockers are first rejected at the RX input using an $N$ -path filter. Then, a blocker current cancellation (BCC) technique is used to mitigate the effect of nonlinearity in the transimpedance amplifier. By introducing an auxiliary path in the RX, the OOB linearity of the RX is further improved by means of frequency-translational noise cancellation (FTNC) and split-BCC. The RX prototype fabricated in a 130-nm CMOS process achieves 2.6–3.2-dB noise figure (NF) and tolerates a 0-dBm blocker at a 50-MHz offset with an NF of 4.9 dB. At 40-MHz offset from the local oscillator (LO), the RX exhibits higher +23-dBm out-of-band input-referred inter modulation product of order 3 (OB-IIP3) without FTNC and higher +26 dBm OB-IIP3 with FTNC.

A 40-GHz Mirrored-Cascode Differential Transimpedance Amplifier in 65-nm CMOS

This paper presents a fully differential transimpedance amplifier (TIA) realized in a standard 65-nm CMOS process, where a novel mirrored-cascode (MC) input configuration is proposed for differential signaling, i.e., an NMOS cascode amplifier with a resistive feedback for negative output and its MC amplifier via an ac-coupling capacitor for positive output. For bandwidth extension, the third-order asymmetric transformers were carefully employed. Measured results of the proposed MC differential (MCD) TIA demonstrate 54-dB $\Omega $ transimpedance gain, 40-GHz bandwidth for 50-fF photodiode capacitance, $19.8-\text{pA}/\sqrt {\mathrm {Hz}}$ average noise current spectral density, ±10-ps group delay variation, and 55.2-mW power consumption. Eye diagrams for 32 Gb/s 215 –1 pseudo random binary sequence (PRBS) were measured with the input currents of 100–1.5 mApp. The chip occupies the area of 0.6 mm2 including I/O pads.

Corrections Corrections to “A Wideband Blocker-Tolerant Receiver With Frequency-Translational Resistive Feedback” [May 19 993-1006

In [1] , the last sentence of the Abstract should read as follows: “Beyond 40-MHz offset from the local oscillator, the RX exhibits more than +23 dBm out-of-band third-order input intercept point (OB-IIP3) without FTNC and more than +26 dBm OB-IIP3 with FTNC.” In addition, the definition of OB-IIP3 in the last sentence of the fourth paragraph of Section I should be “out-of-band third-order input intercept point (OP-IIP3).”

Analysis and design of multi-stage wideband LNA using simultaneously noise and impedance matching method

An analytical approach for design optimization of multi-stage LNAs with common source topology is developed. This paper reviews and analyses simultaneous noise and input impedance matching in three different topologies including common source amplifier with inductive degeneration, resistive feedback and dual feedback in order to achieve maximum available gain and minimum possible noise figure (NF). A study on multi-stage LNAs is performed to calculate optimum input impedance of each stage for minimum overall NF while considering the gain and NF of that stage in addition to the effect of noise of the following stages. MATLAB was used to calculate the starting point of design optimization in a multi-stage LNA. The proposed LNA in 0.1-μm GaAs pHEMT process exhibits a gain of 28 dB in the bandwidth of 3 GHz, input impedance matching of −14 dB, output impedance matching of −12 dB and 1-dB gain compression point of 10 dBm.

A 2–20 GHz SiGe HBT single-stage cascode LNA with linearity enhancement

A wideband high-gain low-noise amplifier (LNA) with improved linearity is presented in this paper. To suppress the gain compression of large signal under high gain conditions, the single-stage cascode topology using resistive shunt-shunt feedback and an emmiter degenerate resistor are adopted. Wideband input matching is thus realized in conjunction with the preceding L-type passive network. A passive network inserted between the cascode structure and load enhances the gain bandwidth as well as the impedance matching. The LNA is based on a 0.18μm SiGe HBT BiCMOS process and the post simulation results show that the LNA features 2–20 GHz bandwidth, 16.1–18.1 dB power gain and 2.5–3.7 dB noise figure (NF). It exhibits input 1-dB compression point of −12dBm above 14 GHz and consumes 55 mW power form a 3.3-V supply. The chip size is 0.435 mm2 without pads.

A 10-Gb/s inductorless optical receiver in 0.18-μm SiGe BiCMOS

A 10-Gb/s inductorless optical receiver featuring linear characteristic has been designed and implemented using a 0.18-μm SiGe BiCMOS process. As the input stage of the proposed optical receiver, a transimpedance amplifier (TIA) of a common-emitter and common-collector topology with a feedback resistor incorporates DC offset cancellation (DOC) and automatic gain control (AGC) to improve the linearity and broaden the input dynamic range. Followed by a post amplifier and a 50-Ω output buffer, the measured input sensitivity, overload, and dynamic range of the optical receiver are respectively −19.3 dBm, −4 dBm, and 15.3 dB for a bit-error rate of 10−12 at 10 Gb/s. The whole receiver draws a total current of 24 mA from a 3.3 V supply and the chip has an area of 826 μm × 957 μm.

Thermodynamics of metabolic energy conversion under muscle load

The metabolic processes complexity is at the heart of energy conversion in living organisms and forms a huge obstacle to develop tractable thermodynamic metabolism models. By raising our analysis to a higher level of abstraction, we develop a compact—i.e. relying on a reduced set of parameters—thermodynamic model of metabolism, in order to analyse the chemical-to-mechanical energy conversion under muscle load, and give a thermodynamic ground to Hill’s seminal muscular operational response model. Living organisms are viewed as dynamical systems experiencing a feedback loop in the sense that they can be considered as thermodynamic systems subjected to mixed boundary conditions, coupling both potentials and fluxes. Starting from a rigorous derivation of generalized thermoelastic and transport coefficients, leading to the definition of a metabolic figure of merit, we establish the expression of the chemical-mechanical coupling, and specify the nature of the dissipative mechanism and the so-called figure of merit. The particular nature of the boundary conditions of such a system reveals the presence of a feedback resistance, representing an active parameter, which is crucial for the proper interpretation of the muscle response under effort in the framework of Hill’s model. We also develop an exergy analysis of the so-called maximum power principle, here understood as a particular configuration of an out-of-equilibrium system, with no supplemental extremal principle involved.

A wide band, low direct current drift, low noise preamplifier for a quadrupole mass spectrometer.

In order to measure the low current in the quadrupole mass spectrometer (QMS), we design a novel wide band composite trans-impedance preamplifier. The noise filtering components, which built in the feedback loop of the preamplifier, are designed to reduce the noise of two-stage amplifiers. By using the package with low thermal resistance factor, reducing the power consumption of preamplifiers and reducing the feedback resistance, the temperature drift of baseline signal is reduced. Compared with the traditional composite preamplifier, the novel preamplifier reduces maximum temperature drift amplitude and reduces root mean square of noise. At last, the environmental reliability of QMS detection was improved.

Full-Differential Folded-Cascode Front-End Receiver Amplifier Integrated Circuit for Capacitive Micromachined Ultrasonic Transducers.

This paper describes the design of a front-end receiver amplifier for capacitive micromachined ultrasonic transducer (CMUT). The proposed operational amplifier (op amp) consists of a full differential folded-cascode amplifier stage followed by a class AB output stage. A feedback resistor is applied between the input and the output of the op amp to make a transimpedance amplifier. We analyzed the equivalent circuit model of the CMUT element operating in the receiving mode and obtained the static output impedance and center frequency characteristics of the CMUT. The op amp gain, bandwidth, noise, and power consumption trade-offs are discussed in detail. The amplifier was fabricated using GlobalFoundries 0.18-μm complementary metal-oxide-semiconductor (CMOS) technology. The open loop gain of the amplifier is approximately 65 dB, and its gain bandwidth product is approximately 29.5 MHz. The measured input reference noise current was 56 nA/√Hz@3 MHz. The amplifier chip area is 325 μm × 150 μm and the op amp is powered by ±3.3 V, the static power consumption is 11 mW. We verified the correct operation of our amplifier with CMUT and echo-pulse shown that the CMUT center frequency is 3 MHz with 92% fractional bandwidth.

High-performance fully differential photodiode amplifier for miniature fiber-optic gyroscopes.

Electrical cross coupling is regarded as a major obstacle to achieving high-performance miniature fiber-optic gyroscopes (FOGs), because it can cause dead bands, which are critical errors in FOGs. Using a differential photodiode amplifier has proven to be effective in rejecting coupled interference. However, the conventional three-op-amp instrumentation amplifier cannot provide a miniature FOG's bandwidth requirements, because of the large photodiode capacitance and parasitic capacitance. We present a high-performance, fully differential photodiode amplifier, where the bandwidth limitations are removed by applying a reverse bias to the photodiode and replacing the feedback resistor with a modified tee-network and a DC cancellation loop. For an experimental FOG with a 300 m fiber coil, we demonstrate a fully differential photodiode amplifier with 880 kΩ gain and 3.5 MHz bandwidth. In the FOG performance test, it not only reduces the angular random walk and bias drift, but also eliminates the approximately 1°/h dead band observed in the same FOG using a PINFET receiver, demonstrating its effectiveness in suppressing coupled interference.

Tackling molecular targets beyond PD-1/PD-L1: Novel approaches to boost patients' response to cancer immunotherapy.

In the new era of immunotherapy, which has changed the clinical oncology practice guidelines, there is a pressing need for finding novel approaches to tune up the clinical outcomes of immunotherapy and extend its benefits to a wider cohort of cancer patients. Several non-classical molecular immune targets beyond PD-1/PD-L1 signaling were shown to be engaged as feedback resistance circuits to shut down the antitumor immune response mediated by the classical immune checkpoint inhibitors. Those include T-cell inducible co-stimulator (ICOS), CD40, CD47, V-domain Ig suppressor of T-cell activation (VISTA), cyclin-dependent kinase (CDK)12, enhancer of Zeste homolog 2 (EZH2), toll-like receptors (TLRs) and OX-40 (CD134). Herein we critically discussed the latest studies concerned with understanding the mechanisms involved in the negative clinical response to classical immunotherapies and strategies to optimize the efficacy of cancer immunotherapy through novel combinatorial approaches.