Author(s): Póvoa, R. ; Arya, R. ; Canelas, A. ; Passos, F. ; Martins, R. ; Lourenço, N. ; Horta, N.
Date: 2020
Persistent ID: http://hdl.handle.net/10400.26/57723
Origin: Escola Superior Náutica Infante D. Henrique
Subject(s): gm-C; OTA; Biquad; Tow-Thomas; Biomedical; Energy-efficiency
This paper presents an innovative topology of a gm-C Operational Transconductance Amplifier (OTA), with improved gain and energy-efficiency and its corresponding implementation inside a second order Tow-Thomas based filter configuration, for biomedical and healthcare applications. The proposed OTA architecture takes advantage of a current division technique, as well as the usage of a pair of cross-coupled voltage-combiners in replacement of the static current source that traditionally bias the differential pair. The circuitry proposed in this paper is described at analytical level, fully-designed at sizing level and validated at simulation level compounded by Monte Carlo results, using a standard 130 nm technology node. Both the OTA and the biquad filter architecture are compared, in terms of performance indexes, with state-of-the-art bibliography, where the potential of both is demonstrated. The designed filter operates at weak inversion and sub-threshold, being supplied by a 0.9 V source, achieving a cut-off frequency of 15 Hz, a gain of 7 dB, hence improving the input-referred noise and consuming nearly 0.55 μW.
