A BiCMOS Implementation of 2nd Order Current Mode ELIN Filters Using the "Tanh" Mapping

In this paper a BiCMOS implementation of second order current mode "tanh" ELIN filter, is presented. The ELIN system is obtained by applying the "tanh" mapping to the prototype filters described by state space equations. The advantages of the proposed structure are: VLSI implementation of three types of filters - low-pass (LP), band-pass (BP) and high-pass (HP) - on the same chip, different possibilities of tuning for center frequency, -3 dB bandwidth, quality factor and operation for a higher dynamic range due to the ELIN system in which the nonlinearities of the active devices are canceling each other, resulting in externally linear, internally non-linear (ELIN) structure. The simulations performed in 0.8 mum BiCMOS technology confirm the theoretical results.