Title :
Investigating the linearity of MOSFET-only switched-capacitor ΔΣ modulators under low-voltage condition
Author :
Parsan, Farhad Alibeygi ; Ayatollahi, Ahmad ; Abrishamifar, Adib
Author_Institution :
Electr. Eng. Dept., Iran Univ. of Sci. & Technol. (IUST), Tehran
Abstract :
Effect of asymmetric operating condition of depletion-mode MOS capacitors on the linearity of MOSFET-only switched-capacitor DeltaSigma modulators is investigated. In very low-voltage switched-capacitor circuits the opamp input and output common-mode levels are separated to provide maximum overdrive voltage for MOS switches. This causes an asymmetric voltage drop on capacitors during operation. On the other hand, the depletion-mode MOS capacitors are most linear when operated under a symmetric condition. The effect of this increased nonlinearity on a DeltaSigma modulator which is operated under an asymmetric condition is simulated and the results are compared with a DeltaSigma modulator which is operated under a symmetric condition.
Keywords :
MOS capacitors; MOSFET; field effect transistor switches; low-power electronics; sigma-delta modulation; MOS switches; MOSFET; common-mode level separation; depletion-mode MOS capacitor; low-voltage condition; switched-capacitor modulator; CMOS technology; Circuit simulation; Linearity; MOS capacitors; MOS devices; Parasitic capacitance; Rails; Switches; Variable structure systems; Voltage; ΔΣ modulator; MOS capacitor; MOSFET-only;
Conference_Titel :
Design and Diagnostics of Electronic Circuits & Systems, 2009. DDECS '09. 12th International Symposium on
Conference_Location :
Liberec
Print_ISBN :
978-1-4244-3341-4
Electronic_ISBN :
978-1-4244-3340-7
DOI :
10.1109/DDECS.2009.5012089
