Title :
Compact sub-hertz OTA-C filter design with interface-trap charge pump
Author :
Becker-Gómez, Adriana ; Çilingiroglu, Ugur ; Silva-Martínez, J.
Author_Institution :
Dept. of Electr. Eng., Texas A&M Univ., College Station, TX, USA
fDate :
6/1/2003 12:00:00 AM
Abstract :
Single-ended and differential operational transconductance amplifier (OTA) configurations are biased with MOSFET interface-trap charge-pumping (ITCP) current generators to achieve very low transconductances for tunable sub-hertz operational transconductance amplifier-capacitor (OTA-C) filter implementation. This paper reviews the basics of ITCP current generation and presents the transconductors and the OTA-C filter configurations based on these transconductors. One of the filters is a low-pass with an experimentally determined lowest cutoff frequency of 0.18 Hz, and the other is a fully differential bandpass with individually tunable lower and upper cutoff frequencies measured down to 0.3 Hz. The former has one 15-pF filter capacitor, and measures 0.0346 mm2, whereas the latter contains four such capacitors and occupies 0.188 mm2 silicon. Experimental evaluation also includes offset, harmonic distortion, and noise performance.
Keywords :
CMOS analogue integrated circuits; active filters; band-pass filters; circuit tuning; differential amplifiers; harmonic distortion; integrated circuit noise; interface states; low-pass filters; operational amplifiers; silicon; 0.18 Hz; 15 pF; MOSFET ITCP current generators; Si; compact sub-hertz OTA-C filter design; differential OTA configurations; fully differential bandpass filter; harmonic distortion; interface-trap charge pump; low transconductances; low-pass filter; noise performance; offset; single-ended OTA configurations; Band pass filters; Capacitors; Charge pumps; Cutoff frequency; Differential amplifiers; Distortion measurement; Frequency measurement; Operational amplifiers; Transconductance; Transconductors;
Journal_Title :
Solid-State Circuits, IEEE Journal of
DOI :
10.1109/JSSC.2003.811981
