Sergio Franco

Bio: Sergio Franco is an academic researcher from San Francisco State University. The author has contributed to research in topics: Amplifier & Operational amplifier. The author has an hindex of 2, co-authored 2 publications receiving 720 citations.

Design with Operational Amplifiers and Analog Integrated Circuits

Abstract: Franco's "Design with Operational Amplifiers and Analog Integrated Circuits, 3e" is intended for a design-oriented course in applications with operational amplifiers and analog ICs. It also serves as a comprehensive reference for practicing engineers. This new edition includes enhanced pedagogy (additional problems, more in-depth coverage of negative feedback, more effective layout), updated technology (current-feedback and folded-cascode amplifiers, and low-voltage amplifiers), and increased topical coverage (current-feedback amplifiers, switching regulators and phase-locked loops). Table of contents 1 Operational Amplifier Fundamentals 2 Circuits with Resistive Feedback 3 Active Filters: Part I 4 Active Filters: Part II 5 Static Op Amp Limitations 6 Dynamic Op Amp Limitations 7 Noise 8 Stability 9 Nonlinear Circuits 10 Signal Generators 11 Voltage References and Regulators 12 D-A and A-D Converters 13 Nonlinear Amplifiers and Phase-Locked Loops

Mutual compensation of mobility and threshold voltage temperature effects with applications in CMOS circuits

Abstract: Mutual compensation of mobility and threshold voltage temperature variations may result in a zero temperature coefficient bias point of a MOS transistor. The conditions under which this effect occurs, and stability of this bias point are investigated. Possible applications of this effect include voltage reference circuits and temperature sensors with linear dependence of voltage versus temperature. The theory is verified experimentally investigating the temperature behavior of a simple voltage reference circuit realized in 0.35 /spl mu/m CMOS process.

A CMOS analog front-end IC for portable EEG/ECG monitoring applications

Abstract: A new digital programmable CMOS analog front-end (AFE) IC for measuring electroencephalograph or electrocardiogram signals in a portable instrumentation design approach is presented. This includes a new high-performance rail-to-rail instrumentation amplifier (IA) dedicated to the low-power AFE IC. The measurement results have shown that the proposed biomedical AFE IC, with a die size of 4.81 mm/sup 2/, achieves a maximum stable ac gain of 10 000 V/V, input-referred noise of 0.86 /spl mu/ V/sub rms/ (0.3 Hz-150 Hz), common-mode rejection ratio of at least 115 dB (0-1 kHz), input-referred dc offset of less than 60 /spl mu/V, input common mode range from -1.5 V to 1.3 V, and current drain of 485 /spl mu/A (excluding the power dissipation of external clock oscillator) at a /spl plusmn/1.5-V supply using a standard 0.5-/spl mu/m CMOS process technology.

A Low-Dropout Regulator for SoC With $Q$ -Reduction

Abstract: A low-dropout regulator for SoC, with an advanced Q-reduction circuit to minimize both the on-chip capacitance and the minimum output-current requirement down to 100 muA, is introduced in this paper. The idea has been implemented in a standard 0.35-mum CMOS technology (VTHN ap 0.55 V and |VTHP| ap 0.75 V). The required on-chip capacitance is reduced to 6 pF, comparing to 25 pF for the case without Q-reduction circuit. From the experimental results, the proposed regulator-circuit implementation enables voltage regulation down to a 1.2-V supply voltage, and a dropout voltage of 200 mV at 100-mA maximum output current.

Current source design for electrical impedance tomography.

Abstract: Questions regarding the feasibility of using electrical impedance tomography (EIT) to detect breast cancer may be answered by building a sufficiently precise multiple frequency EIT instrument. Current sources are desirable for this application, yet no current source designs have been reported that have the required precision at the multiple frequencies needed. We have designed an EIT current source using an enhanced Howland topology in parallel with a generalized impedance converter (GIC). This combination allows for nearly independent adjustment of output resistance and output capacitance, resulting in simulated output impedances in excess of 2 GΩ between 100 Hz and 1 MHz. In this paper, the theoretical operation of this current source is explained, and experimental results demonstrate the feasibility of creating a high precision, multiple frequency, capacitance compensated current source for EIT applications.

Liquid-level measurement system based on a remote grounded capacitive sensor

Abstract: This paper describes the design and implementation of a liquid-level measurement system based on a remote grounded capacitive sensor. The electrodes of the capacitive sensor are built with affordable materials: a rod of stainless steel and a PTFE-insulated wire. The interface circuit relies on a simple relaxation oscillator and a microcontroller. A cable with active shielding interconnects the sensor to the interface circuit. The stability of the active-shielding circuit is analysed by taking into account the parasitic components of both the interconnecting cable and the sensor. The system has been experimentally tested by measuring the level of tap water in a grounded metallic container. Over a level range of 70 cm, the system has a non-linearity error smaller than 0.35 mm and a resolution better than 0.10 mm for a measuring time of 20 ms.