AD7873ARQZ-REEL

Overview

The AD7873ARQZ-REEL is a 12-bit successive approximation analog-to-digital converter (ADC) designed for touch screen digitizer applications. It operates from a single 2.2 V to 5.25 V supply and supports throughput rates up to 125 kSPS. The device integrates on-chip switches for driving resistive touch screens, an internal 2.5 V reference, and a temperature sensor. Key features include direct battery measurement capability, programmable resolution, and a high-speed synchronous serial interface. It is available in 16-lead QSOP, TSSOP, and LFCSP packages.

Feature Summary

• 12-bit ADC with 125 kSPS throughput rate
• Integrated 4-wire touch screen interface with low on-resistance switches
• On-chip 2.5 V reference and temperature sensor (-40°C to +85°C)
• Direct battery measurement input (0 V to 6 V range)
• Shutdown mode with maximum current consumption of 1 µA

Applications

• Personal digital assistants
• Smart hand-held devices
• Touch screen monitors
• Point-of-sale terminals
• Pagers

Procurement Notes

Verify the specific package variant (QSOP, TSSOP, or LFCSP) required for the design, as the base part number covers multiple physical footprints. Confirm that the REEL suffix indicates tape-and-reel packaging suitable for automated assembly processes. Ensure compatibility with the target system's voltage levels and serial clock requirements before procurement.

Selection Notes

Select this component for battery-powered systems requiring low power consumption and integrated touch screen drive capabilities. The ratiometric conversion mode helps eliminate errors caused by on-board switch resistances. Consider the internal reference stability and temperature accuracy if external references are not utilized. Verify that the source impedance of the touch panel allows for sufficient acquisition time within the specified DCLK frequency limits.

Part Context

The AD7873 is part of Analog Devices' family of touch screen controllers and ADCs. It is functionally related to parts like the AD7870 and AD7875 but offers specialized integration for resistive touch panels. The ARQZ suffix typically denotes a specific package type and lead finish, often associated with the 16-lead QSOP or similar small outline packages depending on the manufacturer's coding conventions.

Replacement Considerations

Check datasheets for alternative touch screen controllers such as the AD7870 or ADS7843 series. Ensure pinout compatibility and electrical specifications match, particularly regarding supply voltage ranges and serial interface timing. Verify that any substitute maintains the required 12-bit resolution and throughput speed for the application.