Title :
Design of OTAs for ultra-low-power sigma-delta ADCs in medical applications
Author :
Yeknami, Ali Fazli ; Qazi, Fahad ; Dabrowski, Jerzy J. ; Alvandpour, Atila
Author_Institution :
Dept. of Electr. Eng., Linkoping Univ., Linkoping, Sweden
Abstract :
High-resolution sigma-delta ADCs are gaining significant interest in ultra-low-power medical applications, where accurate measurement of low-frequency and weak electrophysiological signals is required. Operational transconductance amplifiers (OTA) are the key analog component and the most power-hungry part of the sigma-delta (ΣA) modulators. This paper presents a study of OTAs for ultra-low-power operation, including design and a comparative analysis of four OTA architectures implemented in 65nm CMOS Technology. The requirements for OTA gain and GBW are driven in terms of ΣA ADC specifications. The OTAs´ impact on modulator SNR has been investigated by simulation. The results show that a two-stage OTA with load compensation yields highest SNR and lowest power dissipation amongst the four OTAs in this study.
Keywords :
CMOS integrated circuits; bioelectric phenomena; biomedical electronics; biomolecular electronics; low-power electronics; operational amplifiers; sigma-delta modulation; ΣA modulator; CMOS technology; OTA architecture; OTA gain; high-resolution sigma-delta ADC; load compensation; low-frequency signal; medical application; operational transconductance amplifier; power dissipation; sigma-delta modulator; size 65 nm; two-stage OTA; ultra-low-power sigma-delta ADC; weak electrophysiological signal; CMOS integrated circuits; Gain; Mirrors; Modulation; Signal to noise ratio; Topology; Transistors;
Conference_Titel :
Signals and Electronic Systems (ICSES), 2010 International Conference on
Conference_Location :
Gliwice
Print_ISBN :
978-1-4244-5307-8
Electronic_ISBN :
978-83-9047-4-2
