Low Voltage Controller for Touch Screens

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Product Details

The AD7879/AD7889 are 12-bit successive approximation analog-to-digital converters (SAR ADCs) with a synchronous serial interface and low on-resistance switches for driving 4-wire resistive touch screens. The AD7879/AD7889 work 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 AD7879/AD7889 contain a preprocessing block. The prepro- cessing 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 AD7879/AD7889 can run in slave mode or standalone (master) mode, using an automatic conversion sequencer and timer.

The AD7879/AD7889 have 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 (DAVINT), or as a pen-down interrupt when the screen is touched (PENIRQ). The AD7879/AD7889 offer temperature measurement and touch-pressure measurement.

The AD7879 is available in a 12-ball, 1.6 mm × 2 mm WLCSP and in a 16-lead, 4 mm × 4 mm LFCSP. The AD7889 is available in a backside-coated version of the WLCSP. Both parts support an SPI interface (AD7879/AD7889) or an I2C® interface (AD7879-1/AD7889-1). AD7879W and AD7879-1W models are qualified for automotive applications.


  • Personal digital assistants
  • Smart handheld devices
  • Touch screen monitors
  • Point-of-sale terminals
  • Medical devices
  • Cell phones

Product Lifecycle

checked Production

At least one model within this product family is in production and available for purchase. The product is appropriate for new designs but newer alternatives may exist.

Evaluation Kits


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Product Details

This page contains evaluation board documentation and ordering information for evaluating the AD7879 and AD7879-1.

For use with AD7879 Evaluation Board. The software must be installed before the board is plugged in to the USB port on the PC. If the board is has been plugged in before the software is installed, you may need to update the driver. Do this by right clicking on My Computer, select Properties, then Device Manager, then Universal Serial Bus controllers. Right click on the USB device with the yellow "!" next to it and select Update Driver.

Software & Systems Requirements


Design Resources

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ADI has always placed the highest emphasis on delivering products that meet the maximum levels of quality and reliability. We achieve this by incorporating quality and reliability checks in every scope of product and process design, and in the manufacturing process as well.  "Zero defects" for shipped products is always our goal.

AD7879 Material Declaration
PCN-PDN Information Quality And Reliability Symbols and Footprints



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The USA list pricing shown is for BUDGETARY USE ONLY, shown in United States dollars (FOB USA per unit for the stated volume), and is subject to change. International prices may differ due to local duties, taxes, fees and exchange rates. For volume-specific price or delivery quotes, please contact your local Analog Devices, Inc. sales office or authorized distributor. Pricing displayed for Evaluation Boards and Kits is based on 1-piece pricing.

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Evaluation Boards Pricing displayed is based on 1-piece.
Pricing displayed is based on 1-piece. The USA list pricing shown is for budgetary use only, shown in United States dollars (FOB USA per unit), and is subject to change. International prices may vary due to local duties, taxes, fees and exchange rates.