A 1-V 50-MHz Pseudodifferential OTA With Compensation of the Mobility Reduction

This brief presents a high-linearity operational transconductance amplifier (OTA) based on pseudodifferential structures. The linearity is improved by mobility compensation techniques as the device size is scaled down to achieve high speed operation. Transconductance tuning could be achieved by a MOS operating in the linear region. The OTA fabricated in the 0.18-mum CMOS process occupies a small area of 4.5 x 10^-3 mm^-2. The measured third-order intermodulation (IM3) distortion with a 400 mV_PP differential input under 1-V power supply voltage remains below -52 dB for frequency up to 50 MHz. The static power consumption is 2.5 mW. Experimental results demonstrate the agreement with theoretical analyses.