Analogue integrated circuit design has played an important role in the development of integrated circuit technology. As the level of integration increased in integrated circuit technology, digital circuit implementation became more desirable than analogue circuit implementation because of its robustness and simplicity of design. However, an all-digital implementation of complex integrated circuits is only found in certain types of applications such as memories and microprocessors and even in these integrated circuits, various types of analogue circuits are used. At the present time, a typical applications specific integrated circuit (ASIC) might contain 80% digital and 20% analogue circuits. The focus of this book represents techniques for achieving higher performance in analogue circuits in the face of VLSI technologies. Current mode analogue signal processing offers some important speed advantages over voltage signal processing.