Buffer Stage Research Articles

A High Sensitivity CMUT-Based Passive Cavitation Detector for Monitoring Microbubble Dynamics During Focused Ultrasound Interventions.

Tracking and controlling microbubble (MB) dynamics in the human brain through acoustic emission (AE) monitoring during transcranial focused ultrasound (tFUS) therapy are critical for attaining safe and effective treatments. The low-amplitude MB emissions have harmonic and ultra-harmonic components, necessitating a broad bandwidth and low-noise system for monitoring transcranial MB activity. Capacitive micromachined ultrasonic transducers (CMUTs) offer high sensitivity and low noise over a broad bandwidth, especially when they are tightly integrated with electronics, making them a good candidate technology for monitoring the MB activity through human skull. In this study, we designed a 16-channel analog front-end (AFE) electronics with a low-noise transimpedance amplifier (TIA), a band-gap reference circuit, and an output buffer stage. To assess AFE performance and ability to detect MB AE, we combined it with a commercial CMUT array. The integrated system has 12.3 - [Formula: see text] receive sensitivity with 0.085 - [Formula: see text] minimum detectable pressure (MDP) up to 3 MHz for a single element CMUT with 3.78 [Formula: see text] area. Experiments with free MBs in a microfluidic channel demonstrate that our system is able to capture key spectral components of MBs' harmonics when sonicated at clinically relevant frequencies (0.5 MHz) and pressures (250 kPa). Together our results demonstrate that the proposed CMUT system can support the development of novel passive cavitation detectors (PCD) to track MB activity for attaining safe and effective focused ultrasound (FUS) treatments.

Year-round carryover effects are driven by migration phenology for Hirundo rustica (Barn Swallow) wintering in West Africa

Abstract Recently, population declines have been reported for many migratory birds. Because of complex life cycles, determining the causes for such declines is often difficult. Thus, migratory birds are of special conservation interest. We studied the migratory behavior of Hirundo rustica (Barn Swallow) tagged with solar geolocators and determined carryover effects during the entire annual cycle from one breeding season to the next. We used a partial least squares path model (PLS-PM) to disentangle migratory and breeding events that occur in chronological order. In addition, we controlled for broad environmental conditions in the wintering grounds (NDVI and latitude) and the specific molting habitat (δ13C). We did not find a carryover effect from reproduction investment in the attachment year to breeding success in the subsequent year. Individuals that invested more in reproduction departed earlier from the breeding colonies, but this in turn did not affect the onset of autumn migration. Thus, the premigratory period should be acting as a buffer stage counteracting any previous carryover effects from reproduction investment. On the other hand, we found a long-lasting domino effect from the onset of autumn migration to subsequent breeding success, consistent with the notion of a migratory race. Specifically, individuals which started earlier in the autumn migration arrived earlier to the wintering grounds, started earlier in the spring migration arrived earlier to the breeding colonies, and had a higher breeding success. We highlight that the premigratory period (i.e., the time elapsed between departure from breeding areas and the onset of autumn migration) should be important for the life cycle of migratory species, but it has been frequently overlooked.

High data rate and energy efficient configurable IR-UWB transmitter with an integrated balun

This paper presents a novel, digitally configurable, switching oscillator-based impulse radio ultra-wideband (IR-UWB) transmitter that is robust to process variations. The pulse width and pulse position properties of the output waveform are configurable to ensure operation for the desired bandwidth and output pulse energy values. The architecture is based on a cross-coupled LC voltage-controlled oscillator (LC VCO) implemented with a custom-designed on-chip balun at a center frequency of 2.4 GHz. With the usage of this on-chip balun, the need for an extra buffer stage is eliminated, and the highest possible efficiency is achieved with the proper turns ratio selected. The generated digital control pulse signals are also used to ensure fast start-up and UWB operation while maintaining low power consumption with an implemented on/off tail switching scheme. The presented IR-UWB transmitter that occupies a total area of 0.35 mm2 is fabricated in the United Microelectronics Corporation (UMC) 180-nm mixed-mode/radio frequency (RF) CMOS process. The measured output voltage swing of the fabricated transmitter is 0.812 V on a 50-Ω load for the 200 Mb/s data rate, and the bandwidth is measured as 902 MHz. The achieved frequency tuning range is 1 GHz and the fabricated transmitter can drive 50 Ω, 75 Ω and 100 Ω loads with measured efficiency values 4.16%, 5.76%, and 4.05%, respectively. Compared to other works in the literature, this design achieves a higher output pulse energy at a higher data rate while maintaining low power consumption and, thus, high efficiency.

A Ku band low-voltage and low-power CMOS low-noise amplifier with bulk isolation techniques

Abstract In this paper, a broadband(12-18G) low-noise amplifier (LNA) using 65-nm CMOS technology for satellite communication is presented. This LNA was designed in a cascode common source with inductive degeneration topology. In addition, the bulk isolation technique is employed to make the proposed LNA have a higher gain. Furthermore, a two-stage cascaded configuration combined with inductive parallel peaking technology is utilized to make the LNA achieve a wide operating band. For validation, we design this LNA in a 65nm CMOS technology. The simulated results show that S21 of 17.7dB ± 0.5dB, the input/output return loss of -10dB to -33dB and -12dB to -23dB, respectively. It offers the minimum noise figure (NF) performance of 3.33dB, reverse isolation(S12) better than 60dB, and third-order input point (IIP3) of -22.8 dBm obtained over the band of interest. Excluding the output buffer stage, the LNA is consuming 5.1 mW at a supply voltage of 0.8V and its layout area occupies 0.205 mm2.

Development of a New Bioequivalent Omeprazole Product.

Background and Objectives: The enteric form of omeprazole is one of the most commonly prescribed medications. Similarly to Europe, Kazakhstan relies on the localization of pharmaceutical drug production as one of its primary strategies to ensure that its population has access to affordable and good-quality medicines. This study comprehensively describes the technologically available development of bioequivalent delayed-release omeprazole. Materials and Methods: Various regimes and technological parameters were tested on laboratory- and production-scale equipment to establish a technical process where a functional and gastro-protective layer is essential. According to the ICH guidance on stability testing and Kazakhstan local rules, stability studies were conducted under conditions appropriate for climate zone II. The comparison of the rate and extent of absorption with subsequent assessment of the bioequivalence of the generic and reference drugs after a single dose of each drug at a dose of 40 mg was performed. Results: The quantitative and qualitative composition and technology of producing a new generic enteric form of omeprazole in capsules were developed and implemented at the manufacturing site of solid forms. Dissolution profiles in media with pH 1.2 and 6.8 were proven. During the accelerated six-month and long-term twelve-month studies, the developed formulation in both packaging materials at each control point passed the average weight and mass uniformity test, dissolution test, acid-resistance stage test, buffer stage test, impurity assay, and microbiological purity test and met all the specification criteria. A bioequivalence study in 24 healthy volunteers compared against the innovative drug showed the bioequivalency of the new generic system. The obtained values from the test and reference products were 1321 ± 249.0 ng/mL and 1274 ± 233 ng/mL for Cmax, 4521 ± 841 ng·h /mL and 4371 ± 695 ng·h /mL for AUC0-t, and 4636 ± 814 ng·h /mL and 4502 ± 640 ng·h /mL for AUC0-∞. Conclusions: Using affordable technologies, a bioequivalent generic delayed-release formulation of 20 and 40 mg omeprazole has been developed.

5-GHz Injection-Locked Delay Cell With 10–25 ns Adjustable Group Delay in SiGe BiCMOS

This paper presents an on-chip delay line (DL) unit with an adjustable group delay (GD) between 10 and 25 ns. This active DL is designed based on an injection locked voltage-controlled oscillator (ILVCO) topology, with operation frequency of 5 GHz. Analog GD tuning is achieved through the control voltage of the VCO and the power of the injected signal. The free running phase noise (PN) of the DL at 100 kHz and 10 MHz offsets are -98 and -140 dBc/Hz, respectively, and the DL PN follows the PN of the injected signal in the locked mode. The DL was implemented in a 130-nm SiGe BiCMOS platform, and consumes 1.26 mm2 of silicon area. The power dissipation of the VCO core and buffer stage are 1.68 and 17.7 mW, respectively. To the authors best knowledge, the proposed DL achieves one of the highest GDs among the integrated DL cells.

ПІДВИЩЕННЯ ЯКОСТІ ВІБРАЦІЙНОЇ ДІАГНОСТИКИ ВУЗЛІВ ТА АГРЕГАТІВ АГРАРНОЇ ТЕХНІКИ

It is known that friction and vibrations are the main factors affecting the condition of the equipment during its operation. Therefore, monitoring and diagnostics of vibration resistance of machines and mechanisms are of great importance for their effective operation. This article will present and describe methods of vibroacoustic diagnostics, which are simple and sensitive for detecting defects in various mechanisms and machines, in particular in the agricultural sector. One of the key elements used to diagnose and control the degree of wear of parts is a piezoelectric transducer. It is easy to use and highly accurate. Such converters are almost not affected by electric and magnetic fields, acoustic signals and other mechanical vibrations, except in certain cases. This article will consider the improvement of the piezoelectric transducer, which can be used to measure the vibration rate of oscillations of elements and assemblies of agricultural machines. The technical solution includes the use of a differential amplifier with buffer stages connected to a basic differential amplifier. This approach allows you to reduce the impact of out-of-band interference and increase measurement accuracy. The use of a common-mode perturbation voltage is also an important element in the improved piezoelectric transducer, helping to provide more accurate results. This article reveals important aspects of vibration diagnostics and offers a new technical solution to improve measurements. It will be useful for specialists in the field of mechanical engineering and agricultural industry, who are interested in effective control and support of machines and mechanisms during their work.

Comparison of In vitro Dissolution Tests of five brands of Diclofenac Sodium delayed release tablets in Moroccan market

This study aims to evaluate the similarity of in-vitro dissolution profiles, of commercially available generics of diclofenac sodium delayed-release tablets, of 25mg strength, with the innovator brand in Moroccan Market. Dissolution profiles for five brands were determined using the paddle method from the United States Pharmacopoeia. For the aptitude verification of the method, in our experimental conditions, linearity and accuracy tests were performed. The rate of dissolution was determined by Ultra-Violet Spectroscopy at 276nm. The assessment between the generics and the brand medicine was carried out under the similarity factor approach. We also presented an overview of the dissolution principles of tablet dosage form, and the pharmacopoeia dissolution test recommendations in our case. To compliance with US pharmacopoeia specifications, the rate of dissolution should be not more than 10% after 2hours in the acid stage, and not less than 75% at 45 minutes in the buffer stage. Furthermore, two dissolution profiles are considered similar when the f2 value is ≥50. According to routine quality control, evaluating the rate dissolution at the final point, all the generic medicines marketed in Morocco, meet the specification of the dissolution testing. However, using the comparison of dissolution profiles, only generic-2 is interchangeable with the innovator brand.

A SIMPLE RP-HPLC METHOD DEVELOPMENT AND VERIFICATION OF THE DISSOLUTION OF BROMELAIN-A COMPLEX MIXTURE OF PROTEOLYTIC ENZYMES, IN DELAYED-RELEASE TABLETS

Objective: To develop a simple, accurate, precise and linear Reverse Phase High-Performance Liquid Chromatographic (RP-HPLC) method and verify for the quantitative estimation (Dissolution) of Bromelain in delayed-release tablets. Methods: The optimized RP-HPLC method for both acid and buffer stage dissolutions of delayed-release tablets uses Zorbax 300 SB-C8 column (150 mm X 4.6 mm; 3.5μ), a mobile phase-A of 0.1% trifluoroacetic acid in water and a mobile phase-B of 0.1% Trifluoroacetic acid in Acetonitrile in the gradient proportion, flow rate of 1.0 ml/min, injection volume of 25 µl, detection wavelength of 280 nm using a UV/PDA detector, column temperature of 40 °C, sample tray/compartment temperature of 5 °C and a run time of 20 min. Results: The developed method gave Bromelain eluting at about 6 min. Bromelain exhibited linearity in the range 53.4-800.6 μg/ml (r2=0.99992). The precision is exemplified by relative standard deviation of 1.3 and 2.3% for acid and buffer stages, respectively. Percentage recovery of the drug was found to be between 90.0 and 110.0 during accuracy studies. Conclusion: A simple, accurate, precise, and linear RP-HPLC method was developed and verified for the quantitative estimation (Dissolution) of Bromelain in tablets and hence this method can be explored for the analysis of Bromelain in tablets in various pharmaceutical industries.

An Optimized Temperature Compensated Ring Oscillator with Low Power Consumption and Low Variation

In this paper a low power ring oscillator with three differential delay stages and one output buffer stage is designed for Radio Frequency Identification (RFID) applications. The proposed oscillator is designed with neural network model and its parameters are optimized with Teaching–Learning Based Optimization (TLBO) algorithm. The central frequency of the oscillator becomes independent of the temperature with the help of two temperature compensation techniques. In the first technique, the PMOS load transistor of each stage is connected to the NMOS diode connected - in series - transistor. Since these two transistors work in complement of each other, the temperature variation of each stage’s output voltage is decreased. In the second technique, the current variation of oscillator stages versus temperature is reduced since the diode connected transistor is employed in the current source structure. The simulation is done in 0.18 µm Complementary Metal-Oxide Semiconductor (CMOS) technology with the help of Cadence software and the chip area of the layout designed with this software is 19×25 µm2. The designed oscillator exhibits the following parameters: a central frequency of 7.5 MHz, the power dissipation is 238 nW and the frequency deviation is 210 ppm/̊C in the temperature range of 0 to 120ºC, the noise phase and the period jitter are -87.05 dBc/Hz and 0.578 ns (rms), respectively, at 100 KHz offset frequency and 10000 clock cycle.

Retrospective analysis of the biopharmaceutics characteristics of solid oral Modified-Release drug products in approved US FDA NDAs designated as Extended-Release or Delayed-Release formulations

BackgroundModified Release (MR) orally administered drugs products [Extended-Release (ER) and Delayed-Release (DR)] differ from Immediate-Release (IR) drug products in their drug release site and/or rate to offer therapeutic advantages. It is important to understand the biopharmaceutics factors that determine how a drug works in the gastrointestinal tract and the various pharmacokinetic properties that determine a drug’s rate of absorption and release in the human body. To better understand the biopharmaceutics characteristics of ER and DR drug products, this study retrospectively analyzed submissions approved by the US Food and Drug Administration (FDA), from 2001 to 2021, and their corresponding review documents. This review work is expected to enhance the readers’ understanding regarding the biopharmaceutics properties that supported approval of these products’ ER claims, as per 21 CFR 320.25(f), and DR claims. MethodsA comprehensive search was conducted using the FDA’s internal New Drug Application (NDA) database for ER and DR oral drug products approved between 2001 and 2021. The search yielded 87 ER applications (23 ER capsules and 64 ER tablets) and 21 DR applications (10 DR capsules, 11 DR tablets) for which electronic records were accessible. These products were analyzed for overall drug product design, dosing frequency compared to the reference (if applicable), degree of fluctuation, dissolution method, and alcohol dose-dumping. ResultsOut of 87 total applications for ER drug products that were assessed, 62% of the ER tablets contained a polymer matrix formulation, and hypromellose (HPMC) was used in 50% of these products. 52% of the ER capsules consisted of polymer beads while about half of the DR drug products contained a non-bead formulation with a combination of polymers. The majority of ER drug products were found to have a reduction in dosing frequency and a decrease in the degree of fluctuation when compared to the IR reference product. The 13 ER drug products that exhibited an increase in degree of fluctuation exhibited general and pharmacodynamic benefits, such as reduced dosing frequency and reduced pill burden. The majority of DR formulations were developed to prevent drug degradation in the stomach, followed by to decrease potential stomach irritation, and lastly for localized release in the colon. The majority of ER drug products had 1:1 ratios of dissolution duration compared to dosing frequency (i.e., the majority of ER drug products had a dissolution duration of 24 h and were dosed every 24 h while those with a dissolution duration of 12 h were dosed every 12 h). The majority of ER applications had single-stage dissolution methods while most DR drug products used biphasic dissolution methods. All of the DR dissolution methods incorporated an acid stage of 2 h and a buffer stage with various timeframes. 53% the DR drug products had a ratio of dissolution duration to dosing frequency of 1:4 (e.g. a dissolution duration of 2 h to a dosing frequency of 8 h) or 1:8 (e.g. a dissolution duration of 2 h to a dosing frequency of 16 h). Of the ER tablets and DR drug products, 72% exhibited no alcohol dose-dumping under in vitro testing conditions. ER capsules, however, did not yield similar results—most of which exhibited alcohol induced dose-dumping. Alcohol dose dumping was mitigated by either in vivo studies or warnings on the drug product label. ConclusionThe results of this study help the reader understand the design, characteristics, and pharmacological advantages of the ER and DR drug products for patient benefit; as well as the regulations governing the FDA’s assessment of ER claims.

A low-power and high-gain frontend for GHz application using trans-impedance amplifier for fast particle detection

In this paper, we present a front-end for gigahertz applications, FGATI, which utilizes a transimpedance amplifier design to amplify the current signal from a diamond particle detector. The transimpedance amplifier design adopts a flipped-voltage-follower-based current-mirror (FVF-CM) topology as the input stage, offering advantages such as low power consumption, large transimpedance gain, gigahertz bandwidth, and reasonable noise levels. The FVF-CM topology was realized to improve noise reduction with a fully differential output configuration. The design was implemented as an ASIC chip using 65 nm CMOS silicon technology. The bandwidth measurement of the FGATI prototype demonstrated a 3-dB bandwidth of 1.2 GHz. Furthermore, the amplifier's power consumption is low, drawing only 7.2 mW/channel from a 1.2 V power supply, including the buffer stage. The measurement of the FGATI output signal indicated an excellent transimpedance gain of 79.2 dBΩ and a noise level of 6.7 mVrms. These findings highlight the feasibility and effectiveness of the proposed front-end design in high-frequency applications.

Design of an Ultra-Wideband High-Efficiency Power Amplifier Based on a Novel Impedance Matching Structure With Three Paths

In this paper, a design method for a high-efficiency power amplifier (PA) with a three-octave operation bandwidth is proposed. A unique impedance matching structure with three paths (TPs) and a series of inverse continuous modes (SICMs) are combined to achieve outstanding performance in terms of operating bandwidth as well as efficiency. Especially, a buffer stage of impedance matching is generated by the proposed TPs structure, which further promotes the expansion of target bandwidth. To verify the proposed methodology, an ultra-wideband PA component is implemented with a 10-W GaN HEMT device. The measurement results demonstrate a fractional bandwidth of 155.6 % from 0.5 to 4.0 GHz, with saturated output power of 39.5–42.2 dBm, drain efficiency (DE) of 57 –79 %, and a large signal gain of 9.5–12.2 dB. These results show that the PA realized by the proposed TPs impedance matching design is suitable for small-base station and multiband applications.

A CAFVF-based output-capacitor-less LDO with PSRR improvement by feed forward and negative capacitance

This paper presents an output-capacitor-less LDO regulator that is implemented in a 0.18μm CMOS process. It is based on an improved cascode flipped voltage follower that uses two buffer stages to improve loop stability and load current. The feed forward PSRR improvement technique and the equivalent negative capacitance PSRR improvement technique are proposed to improve the power supply rejection ratio (PSRR) performance up to 24 dB at 10 kHz and 38 dB at 100 kHz, respectively. The quiescent current is 27.7 μA, enabling a maximum load current of 50 mA with a dropout voltage of 200 mV. It also achieves excellent line regulation of 0.675 mV/V and load regulation of 8.2 μV/mA.

A novel adaptive droop control strategy for SoC balance in PV-based DC microgrids

Battery energy storage systems (BESSs) are generally used as a buffer stage for photovoltaic (PV) power generation to tolerate the output power unpredictability in DC microgrids, in which the State-of-Charge (SoC) balance is a necessary and urgent issue to be solved. To this end, an integral feedforward sliding mode controller (SMC) is adopted to replace the traditionally proportional integral (PI) controller such that the voltage response speed of the converter in each BESS can be significantly enhanced. Further, a novel adaptive droop control strategy for SoC balance with three different working modes is proposed, in which all batteries can be cooperated through three different stages corresponding to their different SoC degrees. Compared with most existing SoC balancing approaches, the proposed SoC strategy can improve the transient performance for the BESSs and their robustness against the volatility of PV output powers. The effectiveness of the proposed SoC balancing strategy is verified through a simulation in a DC microgrid network consisting of several PV generators, batteries, and loads utilizing Simulink/SimPower Systems.

PENENTUAN DISOLUSI PADA OBAT SENYAWA KETOPROFEN SECARA SPEKTROFOTOMETRI

Research on dissolution determination of Ketoprofen compounds by Spectrophotometry. Ketoprofen is a non-steroidal anti-inflammatory drug compound (NSAID) that works as an anti-inflammatory. Anti-inflammatory here is a group of drugs used to reduce inflammation and relieve pain. The dissolution test is a method used to determine the content of active compounds that dissolve in drugs, where the time, temperature and media are set according to the human stomach and intestines, and can find out how much the content of active compounds dissolves in the human intestines and stomach. This dissolution test, then the ketoprofen drug is read by spectrophotometry. Test the dissolution by spectrophotometer at a wavelength of 260 nm using HCl 0.1 N and buffer pH 7.4. The results of the determination of the dissolution test of the active substance on ketoprofen at the acid stage obtained an average of 0.009% and at the pH 7.4 buffer stage obtained an average content of 86.4155%. It can be concluded that the determination of the ketoprofen dissolution test in the sample meets the requirements (MS), in accordance with the specifications of the Internal Standard of PT Novell Pharmaceutical Laboratories, namely at the acid stage not more than 10% of ketoprofen dissolved in 2 hours, and at the pH 7.4 buffer stage it has a requirement of 75%. ketoprofen dissolved in 45 minutes. In the dissolution of acidic media, 0.1 N HCl is used because its condition resembles that of the stomach.

A 60-GHz Variable-Gain Phase Shifter With an Active RL Poly-Phase Filter

A 60-GHz variable-gain phase shifter consisting of an active I/Q generator and Gilbert-cell-based summing amplifier fabricated in a 65-nm bulk CMOS process is presented here. The proposed I/Q signal generator is implemented by inserting an RL poly-phase filter into the interstage node of a cascode amplifier, which provides good interstage matching and results in a finite gain in the I/Q generator. It also provides good isolation characteristics between the I/Q generator and the subsequent vector-summing amplifier due to the common gate buffer stages. Therefore, it minimizes the rms gain and phase errors of the phase shifter by maintaining accurate I/Q signals regardless of the input impedance of the vector-summing amplifier, which varies with the gain and phase states. The vector-summing amplifier is operated by a current-steering digital to analog converter (DAC) to keep the total dc current constant regardless of the gain and phase states, which makes the output return loss constant. The DAC makes the vector-summing amplifier generate an arbitrary vector by determining the sizes of the I and Q vectors, and the double pole, double throw (DPDT) switch determines the quadrants. The rms gain and phase errors of the proposed variable-gain phase shifter show the values of 0.13 dB and 0.36°, respectively, at 60 GHz with 4-bit gain control in a 20-dB dynamic range and 5-bit phase control at 360°. In the 3-dB frequency range of 56.8–64.1 GHz, the rms gain and phase error outcomes are 0.26 dB and 1.44°, respectively. The chip area and overall power consumption are measured and found to be 0.55 mm2 and 14.52 mW, respectively.

Analysis of volleyball players' force generation during jump spike from the perspective of electromyographic characteristics

Purpose The aim of this study was to investigate the force characteristics of novice athletes and professional athletes in completing a cross spike at position four from the perspective of electromyographic characteristics. Methods Ten novice and ten professional athletes were selected as subjects. The electromyographic characteristics of the athletes were obtained by the Noraxon Ultium electromyography (EMG) and compared. Results In the first stage, i.e., the takeoff stage, the activation level of the rectus abdominis and external abdominal obliques was significantly higher in the professional group (p < 0.05). During the second stage, i.e., the stage of flying to hit the ball, the professional group had a higher integrated electromyography (iEMG) value in the trapezius. Moreover, it showed significantly higher muscle contribution from the rectus abdominis (5.59 ± 1.58%), external abdominal obliques (3.67 ± 1.21%), and trapezius (10.12 ± 2.61%) compared to the novice group (p < 0.05). In the third stage, i.e., the stage of landing and buffering, p < 0.05 in the comparison of the iEMG values of trapezius and gluteus maximus between the two groups. Moreover, the professional group exhibited higher muscle activation levels in all muscles except for the gastrocnemius, compared to the novice group (p < 0.05). Conclusions Professional athletes display superior muscle coordination and more effective muscle force generation in the trunk and lower limbs during the execution of the jump spike action.

A Reconfigurable RF Filter With 1%–40% Fractional Bandwidth for 5G FR1 Receivers

This paper presents a radio frequency front-end (RFFE) for 5G New Radio (NR) receivers operating in Frequency Range 1 (FR1). The core of this RFFE is a synthetic fourth-order Q-enhanced RF filter employing gm-boosting, noise-cancelling, capacitive cross-coupling, and forward body-biasing techniques to achieve 1.7 GHz to 6.4 GHz operating range and 1 adjustable fractional bandwidth (FBW). The function of the filter is based on subtracting out-of-phase signals in the passband and in-phase signals in the stopband. Two Q-enhanced LC resonators are utilized for outphasing. The filter is preceded by a low-noise transconductance amplifier, and it is followed by a programmable gain amplifier and a differential buffer stage for the measurement purposes and gain equalization. The experimental results demonstrate that the voltage gain is tunable between 18 and 47 dB with 0.2 dB steps, which leads to an equalized output power in all the filter configurations. Fabricated in 22 nm Fully Depleted Silicon on Insulator (FD-SOI) technology, the RFFE achieves 4.6 dB NF, -14 dBm IB-IIP3, and 26 dBm IB-IIP2 at 4 GHz. Notably, the fourth-order steep roll-off provides 22 dBm OOB-IIP3 at 2WBW frequency offset. The entire RFFE draws 22-45 mA from a 1 V supply and the filter core occupies 0.11 mm2 chip area.

An Inductorless Optical Receiver Front-End Employing a High Gain-BW Product Differential Transimpedance Amplifier in 16-nm FinFET Process

In this paper, a fully-differential transimpedance amplifier (TIA) providing a high gain-BW product (GBP) is introduced. In the proposed architecture, a cascode cross-coupled structure is employed to double the effective transconductance of the cascode devices, improving the BW of the TIA. Moreover, a differential architecture is implemented using an RC high-pass filter along with a buffer stage requiring smaller capacitance and resistance. Furthermore, a single-ended negative capacitance generation (NCG) circuit is employed at the input of the TIA to partially compensate for the input parasitic capacitances. A TIA including the proposed techniques, designed and laid out in a 16-nm FinFET process, demonstrates 57% and 79% better figure-of-merit compared to cascode and conventional TIAs designed along with the proposed TIA for a fair comparison, respectively. Post-layout simulations in companion with statistical analysis are employed to verify the effectiveness of the proposed architecture. From simulation results, the optical receiver achieves a peak transimpedance gain of 58.5 dBΩ, a BW of 14.8 GHz, an input-referred noise of 33.6 pA/Hz, and an eye-opening of 30 mV at a data-rate of 56 Gbps PAM4 and at a bit-error-rate (BER) of 1E-6. The whole circuit consume 49 mW and occupies an active area of 0.0076 mm2.