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MAX11811 TacTouch™ Resistive Touch-Screen Controller


Maxim’s low-power, ultra-small, resistive touch screen controller with haptic driver


MAX11811 TacTouch™ Resistive Touch Screen ControllerMaxim's MAX11811 low-power touch-screen controller operates from a 1.7V to 3.6V single supply, targeting power-sensitive applications such as handheld equipment. The device contains a 12-bit SAR ADC and a multiplexer to interface with a resistive touch screen panel. A digital serial interface provides communications.

This controller includes digital preprocessing of the touch screen measurements, reducing bus loading and application processor (AP) resource requirements. The included smart interrupt function generator greatly reduces the frequency of interrupt servicing to the devices. The MAX11811 enters low-power mode automatically between conversions to save power, making the device ideal for portable applications.

The MAX11811 offers two modes of operation: direct and autonomous. Direct mode allows the AP to control all touch screen controller activity. Autonomous mode allows the MAX11811 to control touch screen activity, thereby freeing the AP to perform other functions. In autonomous mode, the device periodically scans the touch screen for a touch event without requiring host processor intervention. This can be used to reduce system power consumption. An on-chip FIFO is used during autonomous mode to store results and increase effective data throughput and lower system power.

The MAX11811 supports data-tagging, which records the type of measurement performed; X, Y, Z1, or Z2, and the type of touch event; initial touch, continuing touch, or touch release.

This device features a haptic driver to either drive a vibration motor directly or interface with an external piezo actuator driver. The device generates PWM signals that can drive the MAX11835 haptic piezo controller. It includes a general-purpose current DAC output and a general-purpose input that can be used to drive IR and visible LEDs as well as IR photo detectors in applications such as proximity detectors.

The MAX11811 supports the I²C serial bus. The MAX11811ETP+ is available in a 20-pin TQFN package and is specified over the extended industrial temperature range of -40°C to +85°C.

Features

  • Integrated motor haptic driver
  • 400kHz I²C interface
  • 20-pin, 4mm x 4mm TQFN
  • Low-power operation
  • 250µW at VDD = 1.7V, 34.4ksps
  • ESD protection
  • ±8kV HBM (X+, X-, Y+, Y-)
  • Programmable touch-detect pull-up resistors
  • Two operating modes—direct and autonomous
  • Auto power-down control for low-power operation
  • PWM output for MAX11835 haptic piezo controller (HPC)
  • Data tagging provides measurement and touch event information
  • Digital processing reduces bus activity and interrupt generation
  • X/Y coordinate measurement and touch pressure measurement
  • 4-wire touch screen interface
  • Ratiometric measurement
  • 12-bit SAR ADC
  • Single 1.7V to 3.6V supply
  • Data filtering provides noise reduction
  • Aperture mode provides spatial filtering
  • General purpose current DAC output
  • General purpose input
  • Integrated proximity sensing system

Digi-Key P/N Manufacturer P/N Package Description Datasheet
MAX11811ETP+-ND MAX11811ETP+ 20-TQFN IC TOUCH SCREEN 12BIT I2C 20TQFN Datasheet
MAX11811TEVS+-ND MAX11811TEVS+ EVAL KIT FOR MAX11811 Datasheet