Three-decade programmable fully differential linear OTA

Acoustic and sonar analog signal processing applications require design operational transconductance amplifiers (OTAs) that can be configured over wide frequency range in multiple bands and yet achieve low power consumption and low harmonic distortion. A fully differential, linear OTA is presented with digitally programmable transconductance ranging over three-decades of dynamic range. Measurements from a prototype fabricated in a 0.5 μm CMOS process demonstrate a 0.4 nA/V to 0.8 μA/V transconductance range, 40 dB common-mode rejection ratio (CMRR),and -48 dB third-order harmonic distortion, at 12 μW power dissipation.