Rahul Kumar et al Int. Journal of Engineering Research and Applications www.ijera.com ISSN : 2248-9622, Vol. 4, Issue 5( Version 2), May 2014, pp.120-125 www.ijera.com 120 | Page Design of Biquad Universal Filter Using Operational Transconductance Amplifier in 180nm Technology Rahul Kumar, D. S. Ajnar, P. K. Jain Microelectronics and VLSI design Electronics & Instrumentation Department, SGSITS indore, India. Abstract This paper presents concept of universal filter using operational transconductance amplifier (OTA).The 0.18μm CMOS process is used for design and simulation. This OTA has basing current of 50μA with supply voltage ±1.25v. The design and simulation of this OTA is done using CADENCE virtuoso environment with UMC 0.18μm technology file. This paper presents a electronically tunable voltage mode universal biquadratic filter with Three input and single output using two single ended OTA and two capacitors. The proposed filter provides low-pass,High-pass,Band-pass and Band-stop by appropriately connecting the input terminals. The natural frequency and the quality factor can be set orthogonally by adjusting the circuit components.Also the natural frequency can be electronically tuned via the bias currents of OTAs. Keyword-Biquad, universal filter, voltage mode, OTA, CADENCE, IC-implementation. I. INTRODUCTION. Active filter widely applied in the field of electrical engineering. They can be found in cross over network used in a three-way high fidelity loud speaker, portable ECG detection used in front end circuits and touch-tone telephone used for tone decoding. Several active devices were used to realize tunable active filters, i.e. OTA, OP-AMP, CDTA, Second generation current-controlled current conveyor. OTA is widely used to realize linear and non-linear Analog signal processing circuits. It is well known that an OTA provides an electronic tenability, a wide range of its transconductance gain and simple circuitry. Furthermore, OTA-based circuit require no resistors hence they are highly suitable for IC implementation. Considering The no of input and output terminals, these filter can simply be classified into two categories: (1) A single-input and multiple- outpput (SIMO) type and (2) a multiple-input type. Generally, the SIMO filter can simultaneously realize three basic filter functions,i.e., low-pass,band-pass, and high-pass at a time without altering the connection way of the circuits and without input signal matching. However for the realization band- stop function additional addition and subtraction circuits are usually required.The multiple input filter can realize multifunction by altering the way in which the input signals are connected. Compared with the SIMO filter, the multiple-input filter provides a variety of circuit characteristics with different input voltage and usually doesnot require any parameter-matching conditions.In addition, multiple input filter may lead to reduction in the no of active elements used.The active filter using low active components are more suitable for IC implementation and also reduced the power consumption and area of chip when they build in the form of IC. In this paper, a new electronically tunable voltage mode universal biquadratic filter with three inputs and one output using two single ended OTAs and two capacitors is presented.The employment of single ended OTAs makes the circuit more suitable for IC implementation. By appropriately connecting the input terminals, The proposed circuit can provide low pass,band pass,high pass and band stop voltage response without changing the circuit topology. The natural frequency and quality factor can be controlled orthogonally and electronically.cadence virtuoso simulation results are performed to conform the theoretical analysis. II. Proposed circuit The circuit symbol of OTA is shown in fig.1. The characteristic of ideal OTA can be described By Io=gm(V1 - V2) (1). RESEARCH ARTICLE OPEN ACCESS