AR1021-I/ML

Overview

The AR1021-I/ML is a resistive touch screen controller from the Microchip mTouch AR1000 Series, designed for 4-wire, 5-wire, and 8-wire analog sensors. It features a 10-bit resolution with a typical report rate of 140 reports per second. The device supports I2C slave communication at up to 400 kHz and operates on a 2.5V to 5.0V supply. Key specifications include a standby current of 85 µA (typical) at 5V and an operating current of 17 mA during touch detection. It includes 128 bytes of user EEPROM for calibration storage and built-in drift compensation algorithms.

Feature Summary

• Supports 4-wire, 5-wire, and 8-wire analog resistive touch sensors
• I2C slave interface with 7-bit address 0x4D and up to 400 kHz clock rate
• Built-in drift compensation algorithm and 128 bytes of user EEPROM
• Industrial temperature range operation (-40°C to +85°C)

Applications

• Mobile communication devices
• Personal Digital Assistants (PDA)
• Global Positioning Systems (GPS)
• Point of Sale Terminals

Procurement Notes

Verify that the M1 pin is connected to VSS to configure the device for I2C communication mode. Ensure pull-up resistors are installed on SCL and SDA lines, typically between 2.2 kΩ and 10 kΩ. Confirm that the Brown-Out Detection (BOR) threshold meets system requirements, as it is set to 2.2V.

Selection Notes

Select the AR1021-I/ML when I2C connectivity is required for the host microcontroller. For SPI or UART interfaces, consider the AR1021 variants with different suffixes or the AR1011 model respectively. Ensure the touch sensor layer resistance falls within the 50-2,000 Ω typical range for optimal performance.

Part Context

The AR1021 is part of the AR1000 Series, which also includes the AR1011 (UART interface). The 'I' suffix indicates industrial temperature rating, and '/ML' denotes the 20-QFN package. This series is designed to offload processing overhead from the host by handling decoding and filtering internally.

Replacement Considerations

For direct functional replacement in I2C designs, verify compatibility with other AR1021 variants. For UART-based systems, the AR1011 serves as the alternative within the same family. Cross-referencing pinouts and software protocols is necessary when substituting.