Premium
Programmable feedforward linearized CMOS OTA for fully differential continuous‐time filter design
Author(s) -
Szczepanski Stanislaw,
Pankiewicz Bogdan,
Koziel Slawomir
Publication year - 2010
Publication title -
international journal of circuit theory and applications
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.364
H-Index - 52
eISSN - 1097-007X
pISSN - 0098-9886
DOI - 10.1002/cta.602
Subject(s) - operational transconductance amplifier , feed forward , transconductance , operational amplifier , cmos , total harmonic distortion , electronic engineering , control theory (sociology) , linearization , amplifier , differential amplifier , engineering , resistor , filter (signal processing) , spice , electrical engineering , voltage , physics , computer science , nonlinear system , transistor , control (management) , control engineering , artificial intelligence , quantum mechanics
In this paper, a feedforward linearization method for programmable CMOS operational transconductance amplifier (OTA) is described. The proposed circuit technique is developed using simple source‐coupled differential pair transconductors, a feedback‐loop amplifier for self‐adjusting transcoductance ( g m ) and a linear reference resistor ( R ). As a result, an efficient linearization of a transfer characteristic of the OTA is obtained. SPICE simulations show that for 0.35µm AMS CMOS process with a single +3V power supply, total harmonic distortion at 1 V pp and temperature range from −30 to +90°C is less than −49.3 dB in comparison with −35.8 dB without linearization. Moreover, the input voltage range of linear operation is increased. Power consumption of the linearized OTA circuit is 0.86 mW. Finally, the OTA is used to design a third‐order elliptic low‐pass filter in high‐frequency range. The cut‐off frequency of the operational transconductance amplifier‐capacitor (OTA‐C) filter is tunable in the range of 322.6 kHz–10 MHz using the feedforward linearized OTAs with the digitally programmable current mirrors. Copyright © 2009 John Wiley & Sons, Ltd.