A DTMOS-based power efficient recycling folded cascode operational transconductance amplifier

The focus of the present study is on a recycling folded cascode (RFC) operational transconductance amplifier (OTA) in which the transconductance, as well as the slew rate of OTA, are enhanced. RFC OTA, proposed in this study, is employed using a Dynamic Threshold Voltage MOSFET (DTMOS) based differential pair with class AB operation. To achieve class AB operation, an adaptive biasing technique comprising a flip voltage follower is used which boosts the dynamic current and gain-bandwidth product of OTA. Conventional current mirrors are replaced with source degenerated non-linear current mirrors to achieve a better slew rate. The conventional and proposed RFC structures are designed and simulated in a standard 180 nm CMOS process at 1 V supply voltage. The proposed RFC OTA demonstrates a significant enhancement in the performance parameter as 11 dB improvement in the gain as well as 290% more GBW and achieves a slew rate that is nine times better compared to the conventional RFC.