Resistors, Capacitors, Switches

Abstract

An analog integrated circuit is made of active and passive components. Active elements (n-channel or p-channel transistors) have already been described in the previous chapter. This chapter examines the basic properties of integrated passive components, which are: resistors, capacitors and analog switches. Although, as we will see, analog switches are made of one or a couple of MOS transistors (which are active elements), they are here classified in the passive component category because in reality they do not implement any active function. In fact, a switch, is merely a time-variant resistance. The performance of passive elements in monolithic form is quite different from that of the corresponding ideal or discrete versions. Therefore, before starting to consider the design techniques of integrated circuits, we should know their major characteristics and limits.