Reducing the temperature effect on a CMOS transconductance and its application in g/sub m/-C filters

A new negative feedback technique is applied to stabilize changes in the transconductance of a CMOS operational transconductance amplifier (OTA) with temperature variations over the industrial range of -30/spl deg/C to +85/spl deg/C. Since OTAs are used as the basic building blocks in various g/sub m/-C filters, stabilizing the transconductance brings stability in the frequency and quality factor of the filters built from these OTAs. To validate this notion, a second order band-pass filter with 10 MHz center frequency has been built with the temperature stabilized OTAs. The whole system has been implemented in TSMC 0.18 /spl mu/m CMOS technology available through the Canadian Microelectronics Corporation (CMC) and tested in the laboratory. The experimental results show close agreement with the theoretical expectations.