Characterization of a CMOS sensing core for ultra-miniature wireless implantable temperature sensors with application to cryomedicine

• Published in: Medical engineering & physics Vol. 36; no. 9; pp. 1191 - 1196
• Main Authors: Khairi, Ahmad, Thaokar, Chandrajit, Fedder, Gary, Paramesh, Jeyanandh, Rabin, Yoed
• Format: Journal Article
• Language: English
• Published: England Elsevier Ltd 01.09.2014
• Subjects: Algorithms; All-CMOS; Calibration; Cryomedicine; Cryosurgery; Cryosurgery - instrumentation; Cryotherapy - instrumentation; Electric Power Supplies; Equipment Design; Implant; Miniature; Nonlinear Dynamics; Prostheses and Implants; Radiology; Reproducibility of Results; Temperature; Temperature sensor; Thermometers; Ultra low-power; Wireless Technology; Ultra low-power; Implant; Cryosurgery; Miniature; Cryomedicine; All-CMOS; Temperature sensor
• ISSN: 1350-4533; 1873-4030; 1873-4030
• DOI: 10.1016/j.medengphy.2014.05.002

In effort to improve thermal control in minimally invasive cryosurgery, the concept of a miniature, wireless, implantable sensing unit has been developed recently. The sensing unit integrates a wireless power delivery mechanism, wireless communication means, and a sensing core—the subject matter of the current study. The current study presents a CMOS ultra-miniature PTAT temperature sensing core and focuses on design principles, fabrication of a proof-of-concept, and characterization in a cryogenic environment. For this purpose, a 100μm×400μm sensing core prototype has been fabricated using a 130nm CMOS process. The senor has shown to operate between −180°C and room temperature, to consume power of less than 1μW, and to have an uncertainty range of 1.4°C and non-linearity of 1.1%. Results of this study suggest that the sensing core is ready to be integrated in the sensing unit, where system integration is the subject matter of a parallel effort.