AD7879

PRODUCTION

Low Voltage Controller for Touch Screens

Data Sheet (Rev. D) Product Selection Table

Part Models: 10
1ku List Price: Starting From $1.71

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Overview

4-wire touch screen interface
1.6 V to 3.6 V operation
Median and averaging filter to reduce noise
Automatic conversion sequencer and timer
User-programmable conversion parameters
Auxiliary analog input/battery monitor (0.5 V to 5 V)
1 optional GPIO

Interrupt outputs (INT, PENIRQ)
Touch-pressure measurement
Wake-up on touch function
Shutdown mode: 6 μA maximum
12-ball, 1.6 mm × 2 mm WLCSP
16-lead, 4 mm × 4 mm LFCSP

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 a throughput rate 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 preprocessing 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 ADCs, as a battery monitor, or as a general-purpose input/output (GPIO). In addition, a programmable interrupt output can operate in three modes: as a general-purpose interrupt to signal when new data is available (DAV), as an interrupt to indicate when limits are exceeded (INT), 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 devices support an SPI interface (AD7879 / AD7889) or an I²C interface (AD7879-1 / AD7889-1).

APPLICATIONS

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

Part Models: 10
1ku List Price: Starting From $1.71

Documentation

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. View our quality and reliability program and certifications for more information.

Part Model	Pin/Package Drawing	Documentation	CAD Symbols, Footprints, and 3D Models
AD7879-1ACBZ-500R7	12-Ball WLCSP (1.61mm x 2.01mm)	Material Declaration Reliablity Data Package Resources	Ultra Librarian SamacSys
AD7879-1ACPZ-500R7	16-Lead LFCSP (4mm x 4mm w/ EP)	Material Declaration Reliablity Data Package Resources	Ultra Librarian SamacSys
AD7879-1ACPZ-RL	16-Lead LFCSP (4mm x 4mm w/ EP)	Material Declaration Reliablity Data Package Resources	Ultra Librarian SamacSys
AD7879-1WARUZ-RL	16-Lead TSSOP	Material Declaration Reliablity Data Package Resources	Ultra Librarian SamacSys
AD7879-1WARUZ-RL7	16-Lead TSSOP	Material Declaration Reliablity Data Package Resources	Ultra Librarian SamacSys
AD7879ACPZ-RL	16-Lead LFCSP (4mm x 4mm w/ EP)	Material Declaration Reliablity Data Package Resources	Ultra Librarian SamacSys
AD7879WACPZ-R5	16-Lead LFCSP (4mm x 4mm w/ EP)	Material Declaration Reliablity Data Package Resources	Ultra Librarian SamacSys
AD7879WACPZ-RL	16-Lead LFCSP (4mm x 4mm w/ EP)	Material Declaration Reliablity Data Package Resources	Ultra Librarian SamacSys
AD7879WARUZ-RL	16-Lead TSSOP	Material Declaration Reliablity Data Package Resources	Ultra Librarian SamacSys
AD7879WARUZ-RL7	16-Lead TSSOP	Material Declaration Reliablity Data Package Resources	Ultra Librarian SamacSys

Part Models	Product Lifecycle	PCN

Feb 28, 2012 - 11_0175 Shipping Changes for WLCSP Products with 8mm Carrier Tape Width
		PCN11_0175_Form Material_Report Qualification Report Summary Detailed Parts List
AD7879-1ACBZ-500R7	PRODUCTION
May 4, 2016 - 14_0178 Conversion of 3x3mm, 4x4mm and 5x5mm LFCSP Package Outlines from Punch to Sawn and Transfer of Assembly Site to Amkor Philippines
		PCN14_0178_Form Material_Report Detailed Change Description Package Outline Drawing Qualification Results Summary
AD7879-1ACPZ-500R7	PRODUCTION
AD7879-1ACPZ-RL	PRODUCTION
AD7879ACPZ-RL	PRODUCTION
AD7879WACPZ-R5	PRODUCTION
AD7879WACPZ-RL	PRODUCTION
Oct 26, 2009 - 09_0202 Inclusion of Banding Tape for LFCSP REEL7 parts.
		Material_Report PCN09_0202_Form Proposal for Inclusion of Banding Tape
AD7879-1ACPZ-500R7	PRODUCTION

This is the most up-to-date revision of the Data Sheet.

Software Resources

Device Drivers 1

AD7879 Input Touch Screen Digitizer GitHub Linux Driver Source Code

Can't find the software or driver you need?

Evaluation Kits

AD7879 & AD7879-1 Evaluation Boards

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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.