A fully tuneable micropower log-domain filter

We present a section of a second-order low distortion continuous-time filter employing MOSFETs operating in weak inversion. The idea is based upon the recently proposed log-domain filter approach used in bipolar technology. Measured results from a test chip fabricated in 0.8¿ Bicmos process are presented. Chip power consumption is 1¿W and the tuneable frequency range is 100-10kHz.