Using temperature as observable of the frequency response of RF CMOS amplifiers

The power dissipated by the devices of an integrated circuit can be considered a signature of the circuit's performance. Without disturbing the circuit operation, this power consumption can be monitored by temperature measurements on the silicon surface. In this paper, the frequency response of a RF LNA is observed by measuring spectral components of the sensed temperature. Results prove that temperature can be used to debug and observe figures of merit of analog blocks in a RFIC. Experimental measurements have been done in a 0.25 mum CMOS process. Laser probing techniques have been used as temperature sensors; specifically, a thermoreflectometer and a Michaelson interferometer.Peer ReviewedPostprint (author's final draft

Improved functionalization of oleic acid-coated iron oxide nanoparticles for biomedical applications

Superparamagnetic iron oxide nanoparticles can providemultiple benefits for biomedical applications in aqueous environments such asmagnetic separation or magnetic resonance imaging. To increase the colloidal stability and allow subsequent reactions, the introduction of hydrophilic functional groups onto the particles’ surface is essential. During this process, the original coating is exchanged by preferably covalently bonded ligands such as trialkoxysilanes. The duration of the silane exchange reaction, which commonly takes more than 24 h, is an important drawback for this approach. In this paper, we present a novel method, which introduces ultrasonication as an energy source to dramatically accelerate this process, resulting in high-quality waterdispersible nanoparticles around 10 nmin size. To prove the generic character, different functional groups were introduced on the surface including polyethylene glycol chains, carboxylic acid, amine, and thiol groups. Their colloidal stability in various aqueous buffer solutions as well as human plasma and serum was investigated to allow implementation in biomedical and sensing applications.status: publishe

Low Flow Veno-Venous ECMO: An Experimental Study

Clinical use of extracorporeal membrane oxygenation (ECMO) and carbon dioxide removal (ECCO2R) have become well established techniques for the treatment of severe respiratory failure; however they require full cardiopulmonary bypass, representing major procedures with high morbidity. We theorized the possibility of an efficient low flow venavenous extracorporeal membrane gas exchange method. Four mongrel 12kg dogs were submitted to vena-venous extracorporeal membrane gas exchange via a jugular dialysis catheter using a low flow (10 ml/min) roller pump and a membrane oxygenator for a period of four hours. Respiratory rate was set at 4 breaths/min with a FiO2 of 21% and ventilatory dead space was increased. Adequate gas exchange was obtained (pO2 139, pCO2 24, Sat 99.4%), without major hemodynamic changes or hematuria. Our results demonstrate the feasibility of a low flow, less aggressive system. Further research should be considered

Strategies for built-in characterization testing and performance monitoring of analog RF circuits with temperature measurements

This paper presents two approaches to characterize RF circuits with built-in differential temperature measurements, namely the homodyne and heterodyne methods. Both non-invasive methods are analyzed theoretically and discussed with regard to the respective trade-offs associated with practical off-chip methodologies as well as on-chip measurement scenarios. Strategies are defined to extract the center frequency and 1 dB compression point of a narrow-band LNA operating around 1 GHz. The proposed techniques are experimentally demonstrated using a compact and efficient on-chip temperature sensor for built-in test purposes that has a power consumption of 15 μW and a layout area of 0.005 mm2 in a 0.25 μm CMOS technology. Validating results from off-chip interferometer-based temperature measurements and conventional electrical characterization results are compared with the on-chip measurements, showing the capability of the techniques to estimate the center frequency and 1 dB compression point of the LNA with errors of approximately 6% and 0.5 dB, respectively

Using temperature as observable of the frequency response of RF CMOS amplifiers

The power dissipated by the devices of an integrated circuit can be considered a signature of the circuit's performance. Without disturbing the circuit operation, this power consumption can be monitored by temperature measurements on the silicon surface. In this paper, the frequency response of a RF LNA is observed by measuring spectral components of the sensed temperature. Results prove that temperature can be used to debug and observe figures of merit of analog blocks in a RFIC. Experimental measurements have been done in a 0.25 mum CMOS process. Laser probing techniques have been used as temperature sensors; specifically, a thermoreflectometer and a Michaelson interferometer