AD7879ACPZ-RL

Overview

The AD7879ACPZ-RL is a 12-bit successive approximation analog-to-digital converter (SAR ADC) designed for resistive touch screen applications. It operates on a single supply voltage ranging from 1.6 V to 3.6 V and supports a throughput rate of 105 kSPS. The device integrates low on-resistance switches for driving 4-wire resistive touch screens, an internal temperature sensor, and a programmable auxiliary input/battery monitor. It features a preprocessing block with median and averaging filters to reduce noise. The component utilizes a synchronous serial interface and includes user-programmable conversion parameters, automatic sequencer, and interrupt outputs.

Feature Summary

• 12-bit SAR ADC with 105 kSPS throughput rate
• Integrated median and averaging filters for noise reduction
• Supports 4-wire resistive touch screen interfaces
• Operates within 1.6 V to 3.6 V supply range
• Shutdown mode current consumption less than 6 μA

Applications

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

Procurement Notes

Verify the specific package type required for the design, as the AD7879 series is available in both 12-ball WLCSP and 16-lead LFCSP packages. Confirm that the system interface matches the SPI protocol supported by the standard AD7879 model, distinct from the I2C variant. Ensure power supply rails remain within the specified 1.6 V to 3.6 V operational limits to maintain performance specifications.

Selection Notes

Select this component when a low-power, high-resolution digitizer for resistive touch screens is required. The AD7879 is suitable for battery-powered portable devices due to its shutdown mode and wake-up on touch functionality. Consider the LFCSP-16 package for easier surface-mount assembly compared to the WLCSP option. Verify compatibility with the host microcontroller's serial interface timing requirements.

Part Context

The AD7879 belongs to the Analog Devices AD7879/AD7889 family of touch screen controllers. The AD7889 is a backside-coated version of the WLCSP package. Variants such as the AD7879-1 offer an I2C interface instead of SPI. These devices are engineered to provide robust sensing capabilities including temperature measurement and touch pressure estimation for modern portable displays.

Replacement Considerations

Public confirmed substitute part numbers: AD7879WARUZ-RL.