<h1>Zen of Analog Circuit Design </h1><br /><b>RECENTLY UPDATED WITH NEW CONTENT</b><br />From 2011 till 2013, I taught a course titled <b>Analog Design for all</b> which covered concepts starting with MOS transistors and progressed till the design of two-stage amplifiers. The course introduced concepts in a manner that led the student to the <b>synthesis</b> of new circuits, not merely their <b>analysis</b>. But I still felt that there was a more intuitive way to introduce Analog Circuit Design, one that would bring out the beauty of the subject so that the student could ‘stop and smell the roses’. <br /><br />But why a ‘Zen of Analog’…?<br /><br />Because the foundational concepts in Analog closely mirror human relationships! The purpose of this book is to take a simplified and intuitive path to unlock some profound secrets of Analog. The protagonist of this book is Ang-Lao, a medieval monk who brings his insights into the Analog world to solve the challenges in human relationships.<br /><br />The book addresses a problem statement that much of Analog Circuit Design tries to solve - how do you realize an <b>ideal buffer</b>? It starts with the simple concepts of voltage sources and current sources. From the I-V curve of the MOS transistor, we see how it behaves much like a <b>Voltage controlled current source</b> (VCCS). The inherent challenge in getting even a simple two-transistor circuit to work is the conflict arising from having two such current source-like elements in series. The <b>digital inverter</b> is shown to be one such circuit that can function like an <b>analog amplifier</b>, albeit over a narrow range of input voltage. The effect of <b>loading</b> on such a circuit is illustrated graphically and is shown as an added challenge in getting it to work in an analog manner. <br /><br />Having understood the complications involved, we see how through the strikingly simple but immensely powerful concept of <b>feedback</b>, one of the two transistors can be modified subtly to make it behave like a voltage source. In that process, we realize our first approximation to an ideal analog buffer. We then see how manifestations of the same concept leads us to the synthesis of a whole bunch of two transistor circuits - <b>source followers</b>, common source amplifiers with <b>gm-load</b> and with <b>diode-connected load</b>, and <b>differential amplifiers </b>. The concepts used in synthesis of such elegant circuits are also extended to the analysis of much more complex circuits, for example, a <b>Voltage to Current (V2I) conversion</b> circuit. We introduce the concept of small signal parameters, <b>gm, gds</b>, showing the calculations for the gain and output impedance of our circuits, and quantifying how good each of our buffers really are. <br /><br />The narrative switches between concepts of Electronics and the story of Aman-Ra, an engineer from Medieval Egypt. Struggling with his relationships, his guiding light is Ang-Lao, who teaches him the secret to happy relationships.<br /><br />For some, this book will signal the end of the fear of Analog. For others, it will be the start of a love story. <br /><br /><h2>Concepts covered</h2><br />oI-V characteristics of Voltage & Current sources<br />oIdeal & non-ideal sources<br />oControlled sources<br />oActive and passive elements<br />oI-V characteristics of a MOSFET <br />oMOS transistor as a Voltage controlled current source<br />oDigital inverter as Analog amplifier<br />oOperating point<br />oCommon source (CS) amplifier<br />oEffect of loading on a CS amplifier<br />oFeedback<br />oHow can you make a MOSFET behave like a voltage source?<br />oSynthesis of a CS amplifier with diode-connected load<br />oAnalysis of a V2I circuit including an introduction to current mirror<br />oSynthesis of CS amplifier with gm-load<br />oSynthesis of source follower circuit<br />oSmall signal parameters: gm, gds<br />oSmall-signal gain and output impedance <br />oSynthesis of a differential amplifier<br />oSynthesis of an Operational amplifier <br />oRealizing the buffer using the Operational Amplifier