AD7873BRQ

Overview

The AD7873BRQ 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 low on-resistance switches for driving resistive touch screens, an internal 2.5 V reference, and an on-chip temperature sensor. Key specifications include a maximum integral nonlinearity of ±1 LSB (AD7873B1), switch on-resistance of 5 Ω to 6 Ω, and shutdown current consumption of less than 1 µA. It features a synchronous serial interface and programmable resolution.

Feature Summary

• Integrated 4-wire touch screen interface with low on-resistance switches (5–6 Ω typ).
• On-chip 2.5 V reference and temperature sensor covering −40°C to +85°C.
• Direct battery measurement capability (0 V to 6 V input range).
• Shutdown mode reduces current consumption to <1 µA.

Applications

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

Procurement Notes

Verify the specific suffix 'BRQ' against the manufacturer's ordering guide to confirm package type and temperature grade. Confirm availability status as distribution channels may list this component as obsolete or limited stock. Ensure the selected variant matches the required QSOP, TSSOP, or LFCSP form factor for the target PCB design.

Selection Notes

Select the AD7873B1 version for specified performance with ±1 LSB maximum integral nonlinearity. Choose between internal or external reference based on system noise requirements; the internal 2.5 V reference is available for buffering. Ensure the serial clock frequency does not exceed 2 MHz to maintain the 125 kSPS throughput rate. Verify that the source impedance allows for sufficient track-and-hold acquisition time within three DCLK cycles.

Part Context

The AD7873 belongs to the Analog Devices AD7873 family of touch screen controllers. It is functionally similar to the AD7843 but optimized for resistive touch panel driving. The BRQ suffix typically denotes a specific package configuration and temperature range within the broader AD7873 product line, which also includes variants like ARUZ and BRQZ.

Replacement Considerations

Publicly confirmed substitute part numbers are not provided in the verified documentation. Cross-referencing with the AD7843 may be considered for functional compatibility, though pinouts and specific electrical characteristics should be validated against individual datasheets.