1,422 research outputs found
CMOS Non-tailed differential pair
A continuous-time complementary metal-oxide-semiconductor differential pair that does not require the traditional tail current source as a way to control the direct current and common-mode current is presented. Compared with a p-channel long-tailed pair, the proposed non-tailed solution operates under a higher maximum input common-mode voltage that includes (V-DD+V-SS)/2 even under low supply voltages. Experimental measurements on a prototype fabricated in a 0.35-mu m technology (with metal-oxide-semiconductor thresholds greater than 0.6V) confirm this behavior for supply voltages as low as 1.2V, whereas the long-tailed pair with the same technology offers the same capability only for supplies higher than 1.6V
Charter-School Management Organizations: Diverse Strategies and Diverse Student Impacts
Examines the growth of charter school management organizations, characteristics of students served, and use of resources; CMO practices; impact on students, including middle school test scores; and structures and practices linked to positive outcomes
Systematic Comparison of HF CMOS Transconductors
Transconductors are commonly used as active elements in high-frequency (HF) filters, amplifiers, mixers, and oscillators. This paper reviews transconductor design by focusing on the V-I kernel that determines the key transconductor properties. Based on bandwidth considerations, simple V-I kernels with few or no internal nodes are preferred. In a systematic way, virtually all simple kernels published in literature are generated. This is done in two steps: 1) basic 3-terminal transconductors are covered and 2) then five different techniques to combine two of them in a composite V-I kernel. In order to compare transconductors in a fair way, a normalized signal-to-noise ratio (NSNR) is defined. The basic V-I kernels and the five classes of composite V-I kernels are then compared, leading to insight in the key mechanisms that affect NSNR. Symbolic equations are derived to estimate NSNR, while simulations with more advanced MOSFET models verify the results. The results show a strong tradeoff between NSNR and transconductance tuning range. Resistively generated MOSFETs render the best NSNR results and are robust for future technology developments
Performance enhancement in the desing of amplifier and amplifier-less circuits in modern CMOS technologies.
In the context of nowadays CMOS technology downscaling and the increasing demand of high performance electronics by industry and consumers, analog design has become a major challenge.
On the one hand, beyond others, amplifiers have traditionally been a key cell for many analog systems whose overall performance strongly depends on those of the amplifier. Consequently, still today, achieving high performance amplifiers is essential. On the other hand, due to the increasing difficulty in achieving high performance amplifiers in downscaled modern technologies, a different research line that replaces the amplifier by other more easily achievable cells appears: the so called amplifier-less techniques.
This thesis explores and contributes to both philosophies. Specifically, a lowvoltage differential input pair is proposed, with which three multistage amplifiers in the state of art are designed, analysed and tested. Moreover, a structure for the implementation of differential switched capacitor circuits, specially suitable for comparator-based circuits, that features lower distortion and less noise than the classical differential structures is proposed, an, as a proof of concept, implemented in a ΔΣ modulator
A 0.3 V, rail-to-rail, ultralow-power, non-tailed, body-driven, sub-threshold amplifier
A novel, inverter-based, fully differential, body-driven, rail-to-rail, input stage topology is
proposed in this paper. The input stage exploits a replica bias control loop to set the common mode
current and a common mode feed-forward strategy to set its output common mode voltage. This
novel cell is used to build an ultralow voltage (ULV), ultralow-power (ULP), two-stage, unbuffered
operational amplifier. A dual path compensation strategy is exploited to improve the frequency
response of the circuit. The amplifier has been designed in a commercial 130 nm CMOS technology
from STMicroelectronics and is able to operate with a nominal supply voltage of 0.3 V and a power
consumption as low as 11.4 nW, while showing about 65 dB gain, a gain bandwidth product around
3.6 kHz with a 50 pF load capacitance and a common mode rejection ratio (CMRR) in excess of
60 dB. Transistor-level simulations show that the proposed circuit outperforms most of the state
of the art amplifiers in terms of the main figures of merit. The results of extensive parametric and
Monte Carlo simulations have demonstrated the robustness of the proposed circuit to PVT and
mismatch variations
The design of active resistors and transductors in a CMOS technology
Merged with duplicate record 10026.1/2618 on 07.20.2017 by CS (TIS)This thesis surveys linearisation techniques for implementing monolithic MOS
active resistors and transconductors, and investigates the design of linear tunable
resistors and transconductors. Improving linearity and tunability in the presence
of non-ideal factors such as bulk modulation, mobility-degradation effects and mismatch
of transistors is a principal objective. A family of new non-saturation-mode
resistors and two novel saturation-mode transconductors are developed. Where
possible, approximate analytical expressions are derived to explain the principles
of operation. Performance comparisons of the new structures are made with other
well-known circuits and their relative advantages and disadvantages evaluated.
Experimental and simulation results are presented which validate the proposed
linearisation techniques. It is shown that the proposed family of resistors offers
improved linearity whilst the transconductors combine extended tunability with
low distortion. Continuous-time filter examples are given to demonstrate the
potential of these circuits for application in analogue signal-processing tasks.GEC Plessey Semiconductors, Plymout
Parametric Macromodels of Differential Drivers and Receivers
This paper addresses the modeling of differential drivers and receivers for the analog simulation of high-speed interconnection systems. The proposed models are based on mathematical expressions, whose parameters can be estimated from the transient responses of the modeled devices. The advantages of this macromodeling approach are: improved accuracy with respect to models based on simplified equivalent circuits of devices; improved numerical efficiency with respect to detailed transistor-level models of devices; hiding of the internal structure of devices; straightforward circuit interpretation; or implementations in analog mixed-signal simulators. The proposed methodology is demonstrated on example devices and is applied to the prediction of transient waveforms and eye diagrams of a typical low-voltage differential signaling (LVDS) data link
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