MC74HC4066A

The ON/OFF Control pins should be at V_CC or GND logic levels, V_CC being recognized as logic high and GND being
recognized as a logic low. Unused analog inputs/outputs may be left floating (not connected). However, it is advisable to tie unused analog inputs and outputs to V_CC or GND through a low value resistor. This minimizes crosstalk and feedthrough noise that may be pickedup by the unused I/O pins.

The maximum analog voltage swings are determined by the supply voltages V_CC and GND. The positive peak analog voltage should not exceed V_CC. Similarly, the negative peak analog voltage should not go below GND. In the example
below, the difference between V_CC and GND is twelve volts. Therefore, using the configuration in Figure 16, a maximum analog signal of twelve volts peaktopeak can be controlled.

When voltage transients above V_CC and/or below GND are anticipated on the analog channels, external diodes (Dx)
are recommended as shown in Figure 17. These diodes should be small signal, fast turnon types able to absorb the
maximum anticipated current surges during clipping. An alternate method would be to replace the Dx diodes with
MO`sorbs (Motorola high current surge protectors). MO`sorbs are fast turnon devices ideally suited for precise DC protection with no inherent wear out mechanism.