STMicroelectronic's resistive touch screen controller family is used in LCD touch screen applications. A resistive touch screen is a “sandwich” of two layers that, when touched, electrically connects those two layers. By applying voltage alternately to the two layers and reading its value, the X and Y coordinates on the output of the panel are determined. The controller has a certain number of A/D converters reading the voltage out of the panel and translating it into positional data.