Design of Second Order Low Pass and High Pass Filter using Double Gate MOSFET based OTA

Abstract

OTA-C filters are one of the most widely used as continuous time filters. It is because they are fast active integrators, provides low-power operation and tuning of the filter characteristics at higher frequencies. At high frequencies, the OP AMP based active filters has limited performance. We cannot change the values of resistors and inductors but OTA-C filter provides ability to change their values by changing the transconductance of OTA. Second order low and high pass filter structures have widespread applications. The double gate MOSFETs show better performance in the nanometer range of operation. Because it has better control over short channel effects (SCE’s) and other scaling related problems like gate leakage, sub-threshold conduction. Double gate MOSFET is four terminal device and back gate can be used for biasing which can tune the characteristics of circuit. This will provide additional advantage of low power and reduced area. This paper presents second order low pass and high pass filter based on double gate OTA for VHF and UHF frequency applications. The proposed filter consists of two OTAs and two capacitors. This filter shows low sensitivity to passive components, low component count and ease in design.  The simulation results shows pass band frequency of 14MHz and power consumption of 153.4 µwatt. The simulations are done using Tanner EDA version 13.0 at 90nm technology.

Keywords: DG MOSFETs; OTA-C; Analog tunable circuits; Gain; Bandwidth; Double gate; Self cascode technique; Low pass filter; High pass filter.