ISSN (Print): 2328-3491, ISSN (Online): 2328-3580, ISSN (CD-ROM): 2328-3629 American International Journal of Research in Science, Technology, Engineering & Mathematics AIJRSTEM 17- 314; © 2017, AIJRSTEM All Rights Reserved Page 47 Available online at http://www.iasir.net AIJRSTEM is a refereed, indexed, peer-reviewed, multidisciplinary and open access journal published by International Association of Scientific Innovation and Research (IASIR), USA (An Association Unifying the Sciences, Engineering, and Applied Research) Comparative Analysis of Positive Feedback and Darlington Pair based Operational Amplifier at 32m Technology Vinamrata Yadav 1 and Nikhil Saxena 2 1,2 Department of ECE, ITM University Gwalior, AH-43 Bypass, Jhansi Road, Gwalior, Madhya Pradesh 475001, India I. Introduction Op-Amp emerged as a main design block in the analog circuit applications and dominated the market. The situation is now-a-days changing. The modern linear ICs Op-Amp works at lower voltage [1]. Because of their reduced size, versatile and flexible nature, Op-Amps are use in the fields of process control, communications, computers, power and signal source, displays and measuring systems. It is basically termed as a high gain direct coupled amplifier. Analog as well as digital circuits and systems employ Op-Amps as a basic building block. Op- Amp performs arithmetic operations such as addition, subtraction, division, multiplication, integration, differentiation etc. The “Gorden Moore” envisioned that, the number of transistors per chip would quadruple every three years. The shrinking of CMOS technology has been increased every aggressively with ultra-thin sizes [2]. Operational Amplifiers (Op-Amps) are such a crucial component among various analog systems. Operational amplifiers are considered as a crucial building block in analog and mixed circuit systems and the main goal for designing is to ameliorate performance and use the small size components. An operational amplifier can also be defined as a direct coupled high gain amplifier. Basically, the number of amplifier stages appended in a complex way, thus why it is a multistage amplifier [3]. Its internal circuitry comprises of many transistors, resistors and occupies less space. Thus it employs a little package and is exist in the Integrated circuit (IC) form. II. Conventional Two-Stage CMOS Op-Amp Two-stage Op-Amp are the most popular among general purpose Op-Amp because much larger gain can be obtained compared to single stage Op-Amp. Two-stage refers to the number of gain stage in the Op-Amp [4]. The basic two-stage Op-Amp comprises of Two-Stage: first is differential amplifier stage and other is common source stage. Since Op-Amps generally do not employ output buffer so it is limited to drive resistive loads and high capacitive loads [5]. Figure 1: Schematic diagram of Two-Stage Op-Amp Figure 2: Schematic diagram of CMOS two-stage Op-Amp with positive feedback at load. Abstract: Operational amplifiers are employed in several applications including: low-dropout voltage regulators, audio amplifiers and filters. Most of the applications require Op-Amp with improved gain, minimum leakage current, low power along with the high bandwidth. But it is essential to provide a wide range of bandwidth without influencing other performance metrics drastically. In this paper, the positive feedback technique has been described and a novel Darlington Pair approach has been taken to implement an ultra low power high gain CMOS two stage Operational Amplifier. This approach ameliorates gain bandwidth product (GBW) and also confers high gain in 32nm technology. The circuit is simulated at 1V power supply at Room temperature.