The AD7879W is a 12-bit successive approximation analog-todigital converters （SAR ADCs） with a synchronous serial interface and low on-resistance switches for driving 4-wire resistive touch screens. The AD7879W works with a very low power supply—a single 1.6 V to 3.6 V supply—and feature throughput rates of 105 kSPS. The devices include a shutdown mode that reduces current consumption to less than 6 μA. To reduce the effects of noise from LCDs and other sources， the AD7879W contains a preprocessing block. The preprocessing function consists of a median filter and an averaging filter. The combination of these two filters provides a more robust solution， discarding the spurious noise in the signal and keeping only the data of interest. The size of both filters is programmable. Other user-programmable conversion controls include variable acquisition time and first conversion delay; up to 16 averages can be taken per conversion. The AD7879W can run in slave mode or standalone （master） mode， using an automatic conversion sequencer and timer. The AD7879W has a programmable pin that can operate as an auxiliary input to the ADC， as a battery monitor， or as a GPIO. In addition， a programmable interrupt output can operate in three modes： as a general-purpose interrupt to signal when new data is available （DAV）， as an interrupt to indicate when limits are exceeded （INT）， or as a pen-down interrupt when the screen is touched （PENIRQ）。 The AD7879W offers temperature measurement and touch-pressure measurement. The AD7879W is available in a 16-lead， 4.4 mm × 5.0 mm TSSOP and 16-lead 4 mm × 4 mm LFCSP. Both packages support an SPI interface （AD7879W） or an I2 C? interface （AD7879-1W）.