High performance folded cascode OTA using positive feedback and recycling structure

In this paper, a new technique for enhancing the transconductance and low frequency output impedance of recycling folded cascode amplifiers is presented. These improvements were achieved by using a positive feedback and upgrading the recycling structure. The new structure benifits from better transconductance, slew rate, and DC gain in comparison to conventional folded cascode (FC) amplifier. Moreover, the input referred noise and input offset are reduced and the phase-margin is improved. The improved amplifier is simulated in 0.18 µm CMOS technology, demonstrates a DC gain enhancement of 16.4 dB as well as 117.5 MHz increase in gain bandwidth compared with conventional FC configuration. The amplifier consumes 360 µW @ 1.2 V which makes it appropriate for low-voltage applications.