Switching is the most fundamental function in electronics and plays a vital role in every system. Analog and digital bus switches are used in many industrial instruments and consumer devices to implement test interfaces, multiple peripheral and host selection functions, power and clock management, sample and hold circuits, test and debug interfaces, etc. Single Pole Single Throw (SPST), Single Pole Double Throw (SPDT), and Double Pole Double Throw (DPDT) are some of the switch configurations widely used in the industry today. Figure 1 shows some of the common switch configurations. NXP uses innovative circuit and package designs to offer an extensive portfolio of analog switches in single package with sub-ohmic on state resistance for different applications. In this paper, features and applications of NX and LVC analog switches and CBT digital bus switches are discussed in detail.

Some of these switches have a select pin and some have enable pin, for digital control by a master in the design. Schmitt trigger action at select and enable control pins results in higher reliability in noisy conditions. Both normally closed and normally open switch configurations are offered, which find their way in different applications. For example, normally closed switches are commonly used in audio system of TV. Normally, the audio is routed to speakers at all times as long as the switch is closed but when the mute button is pressed, the switch is opened and audio is muted. On the other hand, normally open switches can be used to isolate multiple peripherals from the source and select the required one. For example, video signals can be routed from digital signal processor to external LCD of a notebook PC via docking station, by closing a normally open switch.