MXB7846

Obsolete

2.375V to 5.25V, 4-Wire Touch-Screen Controller with Internal Reference and Temperature Sensor

Data Sheet (Rev. 2) Product Selection Table

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Overview

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

The MXB7846 is an industry-standard 4-wire touch-screen controller. It contains a 12-bit sampling analog-to-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.

The MXB7846 is guaranteed to operate with a supply voltage down to +2.375V when used with an external reference or +2.7V with an internal reference. In shut-down mode, the typical power consumption is reduced to under 0.5µW, while the typical power consumption at 125ksps throughput and a +2.7V supply is 650µW.

Low-power operation makes the MXB7846 ideal for battery-operated systems, such as personal digital assistants with resistive touch screens and other portable equipment. The MXB7846 is available in 16-pin QSOP and TSSOP packages, and is guaranteed over the -40°C to +85°C temperature range.

Applications