AD7879-1ACPZ-500R7

Overview

The AD7879-1ACPZ-500R7 is a 12-bit successive approximation analog-to-digital converter (SAR ADC) designed for low-voltage touch screen applications. It features an I2C-compatible serial interface and integrated switches for driving 4-wire resistive touch screens. Operating on a single supply from 1.6 V to 3.6 V, the device achieves a throughput rate of 105 kSPS. Key specifications include a maximum shutdown current of 6 μA, programmable median and averaging filters for noise reduction, and auxiliary inputs for battery monitoring or general-purpose I/O.

Feature Summary

• Integrated 12-bit SAR ADC with I2C interface
• Low power operation: 1.6 V to 3.6 V supply range
• Throughput rate of 105 kSPS
• Shutdown mode with maximum current consumption of 6 μA
• Programmable median and averaging filters

Applications

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

Procurement Notes

Verify that the specific suffix '-1' in the part number corresponds to the I2C interface variant rather than the SPI interface found in standard AD7879 models. Confirm package availability matches the LFCSP-16 form factor specified in the datasheet. Ensure environmental compliance documentation aligns with project requirements.

Selection Notes

Select this component when an I2C interface is required for touch screen digitization. The AD7879-1 variant differs from the AD7879 by utilizing SDA/SCL pins instead of DOUT/DIN/CS for communication. Consider the 1.6 V minimum supply voltage for compatibility with low-power systems and verify that the 105 kSPS throughput meets system timing constraints.

Part Context

This component belongs to the AD7879/AD7889 family of touch screen controllers manufactured by Analog Devices. The AD7879-1 specifically denotes the version equipped with an I2C-compatible serial interface, distinguishing it from the SPI-based AD7879. Both variants share identical core ADC performance and touch screen driving capabilities.

Replacement Considerations

The AD7879 serves as the primary functional equivalent but utilizes an SPI interface instead of I2C. Designers must account for significant pinout differences, particularly regarding serial data lines and chip select/addressing configurations, when substituting between these variants.