Check out another recent feature added to our site: Use analogue switches to multiplex your signalsWritten by Paul Rako, Technical Editor of our sister site EDN, it looks at the myriad applications and multifaceted specifications of analogue switches, showing that there is more than meets the eye with these ubiquitous little parts.
He begins:
Few IC-schematic symbols are simpler than the one that depicts an analogue switch (Figure 1a). A basic switch comprises just an input, an output, a control pin, and a couple of power-supply pins. Yet, bedazzling complexity hides behind this simple appearance (Figure 1b).
Several specifications, including power-supply voltage and on-resistance, are fundamental to the part's operation. An analogue switch also has many ac specs, such as bandwidth and switching time. All these specs, including leakage current, change - sometimes radically - over temperature. As with all other analogue parts, the switch has specs that all interact and lie along a continuum of values. These specs are not black and white, just shades of gray (Reference 1).Read the full feaure - Use analogue switches to multiplex your signals
Picture - (Figure 1) A simple symbol represents an analog switch, but stray capacitances abound and small inductances occur because of the presence of bond wires (a). The on-resistance is variable with applied signal and power supply, and the capacitors also change with applied voltage (b).
