The AK4181A is a 4-wire touch screen controller that incorporates a 12-bit 125kHz sampling SAR A/D converter. The AK4181A can detect the pressed screen location by performing two A/D conversions. In addition to location, the AK4181A also measures touch screen pressure. On-chip VREF can be utilized for two analog auxiliary inputs and battery monitoring, with the ability to measure voltages from 0V to 5V.