This document describes the features and characteristics of the ALD4211/ALD4212/ALD4213 quad CMOS analog switches, which are designed for ultra low charge injection applications using a single 3V to 12V power source. In the high precision mode, the input signals are connected to COM input pins and the analog switch outputs are the OUT pins. In this connection configuration, a very low charge injection of 0.2pC is achieved when sampling capacitors of 200pF are used. In the general purpose application mode, the COM and the OUT terminals can be reversed, if necessary. The input signals, in this case, are connected to either the COM or the OUT terminals. The outputs of the analog switches are then the OUT or the COM terminals, corresponding to the other terminal of the analog switches.