We present a new theoretical framework to analyze microwave amplifiers based on the dc SQUID. Our analysis applies input-output theory generalized for Josephson junction devices biased in the running state. Using this approach, we express the high-frequency dynamics of the SQUID as a scattering between the participatingmodes. This enables us to elucidate the inherently nonreciprocal nature of g...

A 1.2 V 7-bit 1 GS/s CMOS flash ADC with an interpolation factor of 4 is implemented by using a 0.13 μm CMOS process. A digital calibration of DC reference voltage is proposed for the 1 preamp array to compensate for the input offset voltage of differrential amplifiers without disturbing the high-speed signal path. A 3-stage cascaded voting process is used in the digital encoder block to elimin...

This paper presents a capacitor cross-coupled gm-boosting scheme for differential implementation of common-gate transimpedance amplifier (CG-TIA). A differential transimpedance amplifiers (DTIA) is designed by this scheme using two modified floating-biased CG stage with improved low corner frequency. Despite conventional methods for single-ended to differential conversion that increase the powe...

Applications of MEMS variable capacitive sensors are introduced. The design trade-offs of variable capacitive sense amplifiers are discussed and a chopper stabilized variable capacitive sense amplifier topology is introduced. The chopper stabilized topology has the advantage of not being sensitive to 1/f noise, charge injection noise, kT/C noise, and dc offsets. This circuit was designed to mee...

Class D amplifiers (amps) are conventionally designed as feedforward circuits primarily due to the difficulty of feeding back the digital pulse width modulated output. We analytically investigate the design of Class D amps with feedback and propose a feedback circuit design. We show that the performance of current-art low-power (mWs) low-voltage (1.11.4V) Class D amps embodying our feedback des...

—In this paper, the use of continuous-time implementation in extended-range (ER) incremental sigma-delta analog-to-digital converters is analyzed in order to explore a possible solution to low-power multichannel applications. The operation principle, possible loop filter topologies, and critical issues are considered using a general approach. It is demonstrated that, in order to fully benefit f...

Tuberculosis outbreaks originating in prisons, mines, or hospital wards can spread to the larger community. Recent proposals have targeted these high-transmission institutional amplifiers by improving case detection, treatment, or reducing the size of the exposed population. However, what effects these alternative proposals may have is unclear. We mathematically modeled these control strategies...

The design of frequency-tunable amplifiers is investigated and the tradeoff between linearity, efficiency and tunability is revealed. Several tunable amplifiers using various varactor diode topologies as tunable devices are designed by using loadpull techniques and their performances are compared. The amplifier using anti-series distortion-free varactor stack topology achieves 38% power added e...

Since the xDSL specifications impose stringent linearity requirements to ensure the integrity of the data transferred, current line drivers use linear amplifiers. The downside of these solutions is their power consumption, as the xDSL modulation has a high peak to average ratio, forcing the amplifier to operate in its least efficient region. An alternative is the use of switching amplifiers, wh...

A new method based on adaptive GA(genetic algorithm) for optimizing the parameters of CMOS operational amplifier is presented in this paper. The synthesis of the Op-amp (operational amplifier) can be translated into multiple-objective optimization task, in which a large number of specifications have to be taken into account. Such as DC-gain, bandwidth of unity gain, phase-margin, power, noise a...