Low-power OTA-C Based Tuneable Fractional Order Filters

ibrahim ethem saçu

Abstract


In this study, a low-voltage low-power, simple operational transconductance amplifier (OTA) based fractional order low-pass and high-pass filters of order (n + α) are designed and simulated with CADENCE-PSPICE where 0 < α < 1 and n ≥ 1. The employed transconductance amplifier operates at ± 0.75V. To simulate designed filters, 0.35 μm TSMC CMOS technology parameters are used. The simulation results verify theoretical statements. The power dissipations of simulated low-pass filters of orders 1.3, 1.5, 2.3 and 2.5 are 14.6 nW, 13 nW, 17 nW and 15.3 nW, respectively. For the same filter orders, the corresponding dissipation values of high-pass filters are respectively 45.2 nW, 42.7 nW, 47.5 nW and 45 nW. In addition to the low-power low-voltage operation, another significant advantage of the proposed circuit topologies is that the OTA based low-pass and high-pass topologies provide electronic tuning capability of the orders and frequency responses of the filters without any structural change on these topologies. Therefore, same circuit topology can be used for the different orders of the same filter by just changing the biasing currents of the used OTAs. Additionally, OTA-C based filters offer usage of the grounded capacitors as well as resistorless realization.

Keywords


Fractional filter, fractional circuit, low power

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References


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