Luigi Colalongo

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Thin-film transistors (TFTs), which use zinc oxide (ZnO) as an active layer, were fabricated and investigated in detail. The transport properties of ZnO deposited by spray pyrolysis (SP) on a TFT structure are studied in a wide range of temperatures, electrical conditions (i.e., subthreshold, above-threshold linear, and saturation regions), and at different(More)
An integrated lock-in amplifier for sensor applications is demonstrated. The circuit has been fabricated in a 0.7µm n-well CMOS process with analog features. The equivalent input noise is 17 nV/√Hz at 20 KHz, and the low-pass filter cut-off frequency can be varied in the sub-Hz range. The ability of resolving input steps of 100 nV at 20 KHz in(More)
In this paper, a mathematical model for the dc/dynamic current of organic thin-film transistors is proposed. The model is based on the variable-range hopping transport theory, i.e., thermally activated tunneling of carriers between localized states, and the mathematical expression of the current is formulated by means of the channel accumulation charge. It(More)
In this paper, a new charge pump architecture is presented: it is based on PMOS pass transistors with dynamic biasing of gates and bodies. By controlling the gate and body voltages of each pass transistor, the voltage loss due to the device threshold is removed and the charge is pumped from one stage to the other with negligible voltage drop. Furthermore,(More)
In this paper, a dc/dc converter is presented that can boost very low voltages to the typical supply voltages of current integrated circuits (1.2 V-1.5 V). The converter is based on a new hybrid inductive and capacitive architecture and it is suitable for power harvesting applications too. The measured prototype can supply 1.2 V by converting an input(More)
To the authors knowledge, this is the first time that a paper demonstrates the feasibility of a fully integrated step-up converter based on inductive elements. The prototype is fabricated in the ST M8 0.18-/spl mu/m process, uses a supply voltage of 1.8 V, and provides an output mean voltage of about 6 V at 10 k/spl Omega/ resistive load with a 60-MHz(More)
Short-channel zinc oxide (ZnO) thin-film transistors (TFTs) are investigated in a wide range of temperatures and bias conditions. Scaling down the channel length, the TFT performance is seriously affected by contact resistances, which depend on gate voltage and temperature. To account for the contact resistances, the transistor is ideally split in three(More)
A fully-integrated DC/DC converter for energy harvesting applications is presented. The startup-voltage of the converter is about 140mV, the output voltage exceeds 1.5V, with a power efficiency at least 20%. The architecture for boosting such extremely low voltages is based on an ultra-low-voltage oscillator cross connected to two phase charge pump. The(More)
High-resolution radars require the transmission and reception of extremely high-bandwidth pulses. The generation of such pulses is a challenging task, especially for low power portable applications. In this paper we present a new approach to face this problem. The proposed approach uses a standard negative impedance LC oscillator to generate(More)
A physical-based and analytical drain current model of amorphous indium gallium zinc oxide (a-IGZO) thin-film transistors (TFTs) is proposed. The model considers the combined contribution of both trapped and free charges that move through the a-IGZO film by multiple-trapping-and-release and percolation in conduction band. The model is compared with both(More)