General Description

The MXB7846 is an industry-standard 4-wire touchscreen controller. It contains a 12-bit sampling analogto-digital converter (ADC) with a synchronous serial interface and low on-resistance switches for driving resistive touch screens. The MXB7846 uses an internal +2.5V reference or an external reference. The MXB7846 can make absolute or ratiometric measurements. In addition, this device has an on-chip temperature sensor, a battery-monitoring channel, and has the ability to perform touch-pressure measurements without external components. The MXB7846 has one auxiliary ADC input. All analog inputs are fully ESD protected, eliminating the need for external TransZorb? devices.

Features

? ESD-Protected ADC Inputs

??? ±15kV IEC 61000-4-2 Air-Gap Discharge

??? ±8kV IEC 61000-4-2 Contact Discharge

? Pin Compatible with MXB7843

? +2.375V to +5.25V Single Supply

? Internal +2.5V Reference

? Direct Battery Measurement (0 to 6V)

? On-Chip Temperature Measurement

? Touch-Pressure Measurement

? 4-Wire Touch-Screen Interface

? Ratiometric Conversion

? SPI?/QSPI?, 3-Wire Serial Interface

? Programmable 8-/12-Bit Resolution

? Auxiliary Analog Input

? Automatic Shutdown Between Conversions

? Low Power (External Reference)

??? 270μA at 125ksps

??? 115μA at 50ksps

??? 25μA at 10ksps

??? 5μA at 1ksps

??? 2μA Shutdown Current

Applications

??? Personal Digital Assistants

??? Portable Instruments

??? Point-of-Sales Terminals

??? Pagers

??? Touch-Screen Monitors

??? Cellular Phones