146 research outputs found
Regression modeling for digital test of ΣΔ modulators
The cost of Analogue and Mixed-Signal circuit
testing is an important bottleneck in the industry, due to timeconsuming
verification of specifications that require state-ofthe-
art Automatic Test Equipment. In this paper, we apply
the concept of Alternate Test to achieve digital testing of
converters. By training an ensemble of regression models that
maps simple digital defect-oriented signatures onto Signal to
Noise and Distortion Ratio (SNDR), an average error of 1:7%
is achieved. Beyond the inference of functional metrics, we show
that the approach can provide interesting diagnosis information.Ministerio de Educación y Ciencia TEC2007-68072/MICJunta de Andalucía TIC 5386, CT 30
Design of a CMOS closed-loop system with applications to bio-impedance measurements
This paper proposes a method for impedance measurements based on a closed-loop implementation of CMOS circuits. The proposed system has been conceived for alternate current excited systems, performing simultaneously driving and measuring functions, thanks to feedback. The system delivers magnitude and phase signals independently, which can be optimized separately, and can be applied to any kind of load (resistive and capacitive). Design specifications for CMOS circuit blocks and trade-offs for system accuracy and loop stability have been derived. Electrical simulation results obtained for several loads agree with the theory, enabling the proposed method to any impedance measurement problem, in special, to bio-setups including electrodes.Ministerio de Ciencia e Innovación TEC2007-6807
Programmable low-voltage continuous-time filter for audio applications
The implementation of a continuous-time filter (CTF) useful for audio frequency applications is presented in this paper. The filter functions can be programmed and tuned with two independent control variables. The filter here proposed has been designed to work at 1.5 V of power supply and at a maximum of 0.5 /spl mu/A/OTA for the worst case current consumption. Electrical simulations of a Tow-Thomas biquad (TTB) show the possibility of obtaining low-pass and band-pass filter functions over the 10 Hz-40 kHz frequency range by changing a control current over four decades.Comisión Interministerial de Ciencia y Tecnología TIC-97-064
A CMOS Bio-Impedance Measurement System
This paper proposes a new method for bio-impedance
measurement useful to 2D processing of cell cultures. It allows to
represent biological samples by using a new impedance sensing
method, and exploiting the electrode-to-cell model for both
electrical simulation and imaging reconstruction. Preliminary
electrical simulations are reported to validate the proposal for
Electrical Cell Impedance Spectroscopy (ECIS) applications. The
results reported show that low concentration cell culture can be
correctly sensed and displayed at several frequencies using the
proposed CMOS system.Ministerio de Ciencia e Innovación TEC2007-6807
Semi-empirical model of MOST and passive devices focused on narrowband RF blocks
This paper presents a semi-empirical modeling of MOST and passive elements to be used in narrowband
radiofrequency blocks for nanometer technologies. This model is based on a small set of look-up
tables (LUTs) obtained via electrical simulations. The MOST description is valid for all-inversion regions
of MOST and the data is extracted as function of the gm=ID characteristic; for the passive devices the
LUTs include a simplified model of the element and its principal parasitic at the working frequency
f0. These semi-empirical models are validated by designing a set of 2.4-GHz LNAs and 2.4-GHz and
5-GHz VCOs in three different MOST inversion regions
New analogue switch circuit having very low forward resistance
A new circuit realisation for an analogue switch is reported. The main feature of the proposed design is the low value of the forward resistance as compared with commercial switches. Experimental data confirming the performance of the circuit are also included
A 1.25V FGMOS Filter Using Translinear Circuits
This paper presents a new low voltage/low power filter design based on Floating-Gate MOS (FGMOS) transistors. FGMOS transistors are used as primitives to design linear and non-linear (/spl radic/x) circuits. This technique enables a voltage reduction in strong inversion mode, and gives a new vision of the translinear principle, suitable for low voltage applications. Experimental results for 0.8 /spl mu/m low-pass and band-pass filter prototypes are reported
Simple evaluation of the nonlinearity signature of an ADC using a spectral approach
This work presents a new method to estimate the nonlinearity characteristics of analog-to-digital converters (ADCs). The method is based on a nonnecessarily polynomial continuous and differentiable mathematical model of the converter transfer function, and on the spectral processing of the converter output under a sinusoidal input excitation. The simulation and experiments performed on different ADC examples prove the feasibility of the proposed method, even when the ADC nonlinearity pattern has very strong discontinuities. When compared with the traditional code histogram method, it also shows its low cost and efficiency since a significant lower number of output samples can be used still giving very realistic INL signature values.Spanish Project TEC2007-68072Junta de Andalucia EXC/2005/TIC-92
A micropower log domain FGMOS filter
In this paper, a CMOS implementation of a low voltage micropower logarithmic biquad based on floating gate MOS transistors (FGMOS) is presented. The translinear principle applied to the floating gate MOS transistor leads to an easy implementation of the state-space equations without using the source terminal in the loop. The voltage supply can be reduced and also there is no need of separate wells. The technique is proven in this low/band pass filter working at 1 V with a maximum power consumption of 2 /spl mu/W. The filter parameters can be adjusted in more than two decades, being the upper frequency around 150 kHz
Switched-capacitor neural networks for linear programming
A circuit for online solving of linear programming problems is presented. The circuit uses switched-capacitor techniques and is thus suitable for monolithic implementation. The connection of the proposed circuit to analogue neural networks is also outlined.Comisión Interministerial de Ciencia y Tecnología ME87-000
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