AD7879-1ACBZ-RL

Overview

The AD7879-1ACBZ-RL is a 12-bit successive approximation analog-to-digital converter (SAR ADC) designed for resistive touch screen applications. It features an I²C serial interface and operates on a single supply voltage ranging from 1.6 V to 3.6 V. The device integrates low on-resistance switches for driving 4-wire touch screens, a preprocessing block with median and averaging filters, and an automatic conversion sequencer. Key specifications include a throughput rate of 105 kSPS, shutdown current below 6 μA, and support for auxiliary inputs, battery monitoring, and temperature measurement.

Feature Summary

• I²C-compatible serial interface with configurable addressing via ADD0 and ADD1 pins
• 12-bit SAR ADC with 105 kSPS throughput rate and internal 2 MHz clock
• Integrated median and averaging filters to reduce noise from LCDs and other sources
• Programmable AUX/VBAT/GPIO pin supporting auxiliary input, battery monitor, or general-purpose I/O

Applications

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

Procurement Notes

Verify the specific package type associated with the ACBZ suffix against official documentation, as standard listings often reference LFCSP or WLCSP variants. Confirm that the I²C interface variant (-1) matches the system bus requirements. Check for moisture sensitivity levels and reflow soldering profile compliance during assembly planning.

Selection Notes

Select this component when an I²C interface is required instead of SPI. Ensure the host processor supports the maximum SCL frequency of 400 kHz. Verify that the 1.6 V to 3.6 V operating range aligns with the system power rails. Consider the thermal resistance of the chosen package if high ambient temperatures are expected.

Part Context

This part belongs to the AD7879/AD7889 family of low-voltage touch screen controllers. The -1 suffix denotes the I²C interface variant, distinguishing it from the SPI-based AD7879/AD7889. The ACBZ suffix typically indicates a specific wafer-level chip scale package (WLCSP) configuration, differing from the leaded LFCSP options.

Replacement Considerations

Direct replacements include other AD7879-1 variants with different packaging, such as AD7879-1ACPZ-RL for LFCSP. Cross-family alternatives like the AD7877 require interface adaptation due to SPI-only connectivity.