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
`SPITM/QSPITM, 3-Wire Serial Interface
`Programmable 8-/12-Bit Resolution
`Auxiliary Analog Input
`Automatic Shutdown Between Conversions
`Low Power (External Reference)
270A at 125ksps
115A at 50ksps
25A at 10ksps
5A at 1ksps
2A Shutdown CurrentApplication·
Personal Digital Assistants
·Portable Instruments
·Point-of-Sales Terminals
·Pagers
·Touch-Screen Monitors
·Cellular PhonesPinout
SpecificationsVDD, VBAT, DIN, CS, DCLK to GND ..........................-0.3V to +6V
Digital Outputs to GND...............................-0.3V to (VDD + 0.3V)
VREF, X+, X-, Y+, Y-, AUX to GND................-0.3V to (VDD + 0.3V)
Maximum Current into Any Pin .........................................±50mA
Maximum ESD per IEC-61000-4-2 (per MIL STD-883 HBM)
X+, X-, Y+, Y-, VBAT, AUX ............................................15kV (4kV)
All Other Pins .............................................................2kV (500V)
Continuous Power Dissipation (TA = +70)
16-Pin QSOP (derate 8.30mW/ above +70)...............667mW
16-Pin TSSOP (derate 5.70mW/ above +70) .............456mW
Operating Temperature Range .............................-40 to +85
Junction Temperature........................................................+150
Storage Temperature Range ...............................-65 to +150
Lead Temperature (soldering, 10s) ...................................+300
Stresses beyond those listed under "Absolute Maximum Ratings" may cause permanent damage to the device. These are stress ratings only, and functional operation of the device at these or any other conditions beyond those indicated in the operational sections of the specifications is not implied. Exposure to absolute maximum rating conditions for extended periods may affect device reliability.
DescriptionThe 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.
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 shutdown mode, the typical power consumption is reduced to under 0.5W, while the typical power consumption at 125ksps throughput and a +2.7V supply is 650W.
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 to +85 temperature range.
MXB7846 Data Sheet
