R. Salazar

Drain Current and Transconductance Model for the Undoped Body Asymmetric Double-Gate MOSFET

A surface potential-based drain current and transconductance model for undoped-body asymmetric double-gate MOSFETs are presented. They are built on the basis of the front and back surface potentials and a charge coupling variable evaluated at the source and drain ends. The model consists of single analytic equations which are valid for all bias conditions, from subthreshold to strong inversion and from linear to saturation operation. Its validity has been verified by comparison to numerical simulations

A minimal integral nonlinearity criterion to optimize the design of a new tanh/sinh-type bipolar transconductor

We report on the use of a simple design optimization criterion for obtaining maximum static transfer function linearity. It is based on an analytic function that corresponds to the integral nonlinearity of the circuit. The criterion may be useful, either as an analytic tool to gain insight into the circuits behavior, or as an efficient computational alternative to calculating total harmonic distortion (THD). It is utilized here to optimize the design parameters of a recently proposed bipolar transconductor capable of high linearity, which is composed of two parallel-connected nonlinear blocks: a hyperbolic tangent-type transconductor and hyperbolic sine-type transconductor. Examination of this tanh/sinh-type transconductor concept, using the analytic version of the present criterion, indicates that this new circuit configuration is theoretically capable of achieving values of THD lower than possible with conventional bipolar hyperbolic tangent-type transconductors. A particular design example is presented to demonstrate, through simulations, the performance of the new transconductor, and in order to ascertain the ability of the proposed design optimization criterion for obtaining maximum static transfer function linearity. In this particular example, THD values of less than 0.3% are obtained with a 100-/spl mu/S transconductance up to a maximum input voltage swing of 50-mV peak.

On integration-based methods for MOSFET model parameter extraction

This article reviews integration-based model-parameter extraction methods for MOSFETs. It comprises three different methods that use the transfer characteristics measured under linear regime operation conditions. Additionally two other methods are included for extraction under saturation conditions. An integration-based method to evaluate the location of a maximum value of a given function is also included. Finally, the possibility of evaluating distortion is briefly introduced.

Harmonic distortion in MOSFETs calculated by successive integration of the transfer characteristics

The harmonic distortion of experimental n-MOSFETs with different channel lengths has been studied from their measured transfer characteristics, using a recently proposed alternative mathematical procedure called ¿full successive integrals method¿ (FSIM). The FSIM allows accurate calculation of the Fourier coefficients (Hk) and hence traditional figures of merit such as THD, HDk, IP2 and IP3 can be readily determined. The FSIM circumvents the use of AC analysis (avoids Fourier analysis), and additionally acts as a very efficient filter for the noise which is inherently present in measurement data. Furthermore, the FSIM can successfully determine the harmonic distortion associated with any amplitude of the input signal.

Comments on “A sinh Resistor and Its Application to tanh Linearization”

For original article by M. Tavakoli and R. Sarpeshkar see ibid., vol.40, no.2, p.536-43, Feb.2005

On the Threshold Voltage of Undoped Double-Gate SOI MOSFETs

Threshold voltage provides valuable information about the behavior and reliability of MOSFET devices. In this paper we review and reexamine various definitions of the threshold voltage of undoped double-gate MOSFETs.

Design, optimization and fabrication of a tanh/sinh-type bipolar transconductor with maximum linearity

We have designed, optimized and fabricated a bipolar transconductor with maximum static transfer function linearity. The optimization was based on an analytic function that corresponds to the integral nonlinearity of the circuit. This transconductor is composed of two parallel-connected non-linear blocks: a hyperbolic tangent-type transconductor and hyperbolic sine-type transconductor. The transconductor was fabricated using 0.5 /spl mu/m BiCMOS mixed-signal process. A minimum THD value of 0.2% was obtained with a 100 /spl mu/s transconductance up to a maximum input voltage swing of 50 mV peak.