Highly linear wide input range CMOS OTA architectures operating in subthreshold and strong inversion

A very low distortion low-voltage CMOS OTA with very wide gm adjustment and input range is presented. It is based on a fixed gain novel highly linear voltage-to-current conversion input stage and uses electronically programmable current mirrors to achieve very wide transconductance gain adjustment range. The OTA input range remains approximately constant with gm adjustment. Bandwidth and input signal range can be adjusted independent of gm. Simulations results in 0.5 μm CMOS technology with ±1 V supplies and 1 V input range are presented which confirm the characteristics of the proposed structure.