AR1021T-I/ML

Overview

The AR1021T-I/ML is a resistive touch screen controller from the Microchip mTouch AR1000 Series, housed in a 20-QFN (4x4 mm) package. It supports 4-wire, 5-wire, and 8-wire analog resistive sensors with a maximum 10-bit resolution. The device operates on a 2.5V to 5.0V supply, drawing 17 mA typical current during touch events. It features an I2C slave interface with a 7-bit address of 0x4D, supporting up to 400 kHz. Key specifications include a 140 reports per second coordinate rate, built-in drift compensation, and 128 bytes of user EEPROM for calibration storage.

Feature Summary

• Supports 4-wire, 5-wire, and 8-wire analog resistive touch sensors
• I2C slave communication interface with 7-bit address 0x4D
• 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 the specific ordering suffix 'I/ML' corresponds to the industrial temperature grade and QFN-20 package. Confirm that the I2C interface variant is selected, as the AR1021 series includes SPI and UART variants. Ensure the host system provides the required pull-up resistors for SCL and SDA lines and adheres to the specified voltage levels.

Selection Notes

Select this component when using analog resistive touch screens requiring I2C connectivity. The M1 pin must be connected to VSS to enable I2C mode. Verify sensor compatibility regarding lead-to-lead resistance (50-2,000 Ω) and layer-to-layer capacitance (0-0.5 µF). Consider the 17 mA operating current for power budget calculations.

Part Context

The AR1021T-I/ML belongs to the AR1000 Series, which also includes the AR1011 (UART) and AR1020 (SPI/I2C compatible but without clock stretching on writes). The 'T' indicates tape and reel packaging, while 'I' denotes the industrial temperature range. The 'ML' suffix specifies the 20-VFQFN exposed pad package.

Replacement Considerations

The AR1020 is a functional alternative within the same series but lacks clock stretching on write conditions for I2C. The AR1011 offers UART communication instead of I2C/SPI. Pinouts are identical across the SSOP/SOIC/QFN packages for the series, but interface selection via the M1 pin differs.