Contents INTRODUCTION
Active inductors are found to be applicable in many microelectronic applications e.g. telecommunication instruments, measurement instruments and medical instruments etc. They are also more preferable than their passive counterpart entitled the spiral inductor which is too expensive and incapable to operate at the moderate frequency range (kHz and MHz ranges). It can be seen that these active inductors are constructed based upon the concept of inductor realization using the gyrator-C combination and can be classified into two folds according to the level of their construction basis. Those belong to the first category are constructed at the network level basis by using the available active building block e.g. many types of OP-AMPs and Current Conveyors of many generations etc. as the basis active element for the gyrator construction and use the discrete external capacitor to complete the gyrator-C realization e.g. those proposed in [1]–[4] etc. On the other hand, those belong to the second category are constructed at the transistor level basis by constructing the gyrator directly from the transistors and employ the usage the parasitic capacitors within the transistors e.g. those proposed in [5]–[7] for GaAs Technology and in [8] and [9] for CMOS technology etc. Recently, the OTA has been widely used in filter design [10]. The OTA can be used as the basis active elements for the active inductors entitled the OTAbased inductor which can be both grounded and floating topologies. It can be seen that these topologies of OTA-based inductor can be depicted as follows. The OTA based ground inductor (left) and the OTA-basedfloating inductor (right)
