AR1021-I/SS

Overview

The AR1021-I/SS 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 operates on a 2.5V to 5.0V supply with an operating current of 17 mA during touch detection. It supports I2C and SPI slave communication interfaces. Key specifications include built-in drift compensation, 128 bytes of user EEPROM for calibration storage, and operation within an industrial temperature range of -40°C to +85°C.

Feature Summary

• Supports 4-wire, 5-wire, and 8-wire analog resistive touch sensors with proprietary decoding algorithms.
• Includes 128 bytes of onboard User EEPROM for storing and applying touch calibration data independently.
• Features built-in drift compensation algorithms to maintain accuracy across varying environmental conditions.
• Provides low-power sleep mode with standby currents as low as 40 µA at 2.5V.

Applications

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

Procurement Notes

Verify that the specific part number corresponds to the SSOP-20 package variant. Confirm interface requirements match the AR1021 designation, which supports I2C and SPI protocols, distinct from the UART-only AR1011. Ensure the M1 pin configuration aligns with the selected communication bus in the host design.

Selection Notes

Select the AR1021 when I2C or SPI connectivity is required for the host microcontroller. The M1 pin must be tied to VSS to enable I2C mode. For 5-wire sensor configurations, the M2 pin must be connected to VDD. Verify that the host system can accommodate the 7-bit I2C address of 0x4D or configure the SPI slave select line appropriately.

Part Context

The AR1021 is part of the AR1000 Series, which also includes the AR1011 (UART interface only) and AR1020 (I2C/SPI). The 'I' suffix indicates the industrial temperature grade (-40°C to +85°C), while 'SS' denotes the 20-lead SSOP package. This series is engineered to reduce host processing overhead by handling touch decoding and filtering internally.

Replacement Considerations

The AR1020 serves as a functional alternative within the same series, offering identical I2C and SPI capabilities. When substituting, verify that the firmware supports the specific command set and register map differences between the AR1021 and AR1020 variants.