Title :
A fully integrated CMOS chopper amplifier
Author :
Garrity, Doug ; Young, Jenkuan ; Thelen, Don
Author_Institution :
American Microsyst. Inc., Pocatello, ID, USA
Abstract :
A CMOS chopper amplifier that achieves reduced input offset voltage and fast overload recovery time while maintaining bandwidths comparable to conventional operational amplifiers and requiring no external components is presented. The chopper amplifier consists of two folded cascode operational transconductance amplifiers (OTA) connected in a switched feed-forward configuration, and a third OTA that is used to realize a large capacitive load during normal operation, and a greatly reduced capacitive load during an overload condition. The circuit has been fabricated in a 2 μm CMOS process. The measured input offset voltage is less than 50 μV, the bandwidth is greater than 250 kHz, the maximum overload recovery time is less than 6.5 ms, and the DC gain is greater than 120 dB
Keywords :
CMOS integrated circuits; DC amplifiers; choppers (circuits); 120 dB; 2 micron; 250 kHz; 6.5 ms; CMOS chopper amplifier; OTA; folded cascode; input offset voltage; operational transconductance amplifiers; overload recovery time; switched feed-forward configuration; Bandwidth; CMOS process; Choppers; Circuits; Feedforward systems; Gain measurement; Operational amplifiers; Time measurement; Transconductance; Voltage measurement;
Conference_Titel :
ASIC Conference and Exhibit, 1991. Proceedings., Fourth Annual IEEE International
Conference_Location :
Rochester, NY
Print_ISBN :
0-7803-0101-3
DOI :
10.1109/ASIC.1991.242859
