AD7843ARQ

Overview

The AD7843ARQ 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 features a synchronous serial interface, programmable 8-bit or 12-bit resolution, and two auxiliary analog inputs. Key specifications include a maximum current consumption of 380 µA at 125 kSPS with a 3.6 V supply, ratiometric conversion capability, and a shutdown mode drawing less than 1 µA. It is housed in a 16-lead QSOP package.

Feature Summary

• 12-bit ADC with 125 kSPS throughput rate
• Single supply operation from 2.2 V to 5.25 V
• Ratiometric conversion mode for touch screen accuracy
• Shutdown mode with <1 µA current consumption

Applications

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

Procurement Notes

Verify the 'ARQ' suffix indicates the 16-lead Quarter Size Outline Package (QSOP). Confirm the temperature grade corresponds to the 'A' variant (-40°C to +85°C). Ensure the source document matches Analog Devices datasheet Rev. B for accurate electrical specifications.

Selection Notes

Select this component for battery-powered systems requiring low power and high speed. The ratiometric mode eliminates errors from switch resistance in resistive touch screens. Ensure the external reference voltage is between 1 V and VCC. Check that the serial clock frequency does not exceed 2 MHz.

Part Context

The AD7843 is part of Analog Devices' touch screen controller family. It integrates a track-and-hold amplifier, multiplexer, and SAR ADC. The ARQ designation specifically refers to the plastic QSOP package option, distinct from the TSSOP variant.

Replacement Considerations

Public confirmed substitute part numbers are not provided in the source material.