Adjustably transconductance enhanced bulk‐driven OTA with the CMOS technologies scaling

An adjustably transconductance enhanced bulk‐driven operational transconductance amplifier (OTA) working at weak inversion region is presented. Based on the traditional positive feedback source degeneration technique, a proposed current‐shunt auxiliary amplifier is employed here to modulate the gate of input differential pairs, achieving a further improvement of the effective transconductance with the CMOS technologies scaling. In addition, an adjustable transconductance enhancement factor is obtained, leading to an enhanced stability performance. Both conventional and proposed bulk‐driven OTAs are designed and simulated on CSMC 180 nm process. The simulated results demonstrate that the unity gain‐bandwidth of the proposed bulk‐driven OTA is improved by 120% compared to that of the conventional counterpart with a little neglected increased power consumption.