A New Improved Current Splitter OTA with Higher Transconductance and Slew Rate.

The focus of an amplifier's design engineer is always on its high gain and bandwidth. While larger transistors can produce higher gains, the trade-off is a narrower bandwidth. On the other hand, increasing an amplifier's DC biassing current results in an increase in its bandwidth, but at the expense of higher power consumption. In order to resolve these conflicts, a new structure for dual output operational transconductance amplifier (DOOTA) using current splitting technique has been proposed in this paper. Current splitting concept has been introduced to obtain two different paths for signal current. The proposed current-splitter DOOTA (CS-DOOTA) requires considerably lower count of circuit components. It shows significant increase in bandwidth, while requiring lower operating current, leading to considerable improvements in small-signal figure of merit. Furthermore, to obtain higher transconductance and slew rate, an improved current splitter-DOOTA (ICS-DOOTA) is proposed. The parameters of this ICS-DOOTA can be improved by increasing the splitting ratio (K) of the MOSFETs. This architecture shows improvements in large-signal figure of merit, due to improvement in its slew rate with higher values of K, while possessing the same dimensions and biasing current. All these results have been verified using Ltspice, in 0.18 µm technology. A high gain CDTA has been implemented using ICS-DOOTA, which is further used in the realization of current-mode KHN filters with different current splitting factors. [ABSTRACT FROM AUTHOR]