IO-Link Local Temperature Sensor

The MAXREFDES173# is a complete, high-accuracy, IO-Link®, local temperature sensor reference design that provides excellent temperature accuracy from -40°C to +85°C. Built in an industrial form factor, the design makes use of the Maxim Integrated® MAX31875 digital temperature sensor with an I2C interface.

The MAX31875 operates over the -50°C to +150°C temperature range and measures temperatures from -40°C to +145°C with an accuracy of ±1.75°C or better. The temperature sensor performs more accurate temperature conversions from 0°C to +70°C (±1.0°C).

A Renesas RL78 (R5F10E8EALA) microcontroller interfaces between the MAX31875 temperature sensor and the MAX14827A IO-Link device transceiver. The RL78 microcontroller operates from -40°C to +85°C. The 3.3V and 5V rails are generated by two integrated LDO regulators within the MAX14827A, which reduces the number of required external components and the required circuit footprint. Both the MAX31875 and the MAX14827A are low-power devices, which allow this reference design to consume minimal power with low thermal dissipation. Additionally, both Maxim products are in wafer-level packages (WLPs), giving the MAXREFDES173# a tiny overall footprint.

This sensor utilizes the IQ2 Development™ IO-Link device stack to communicate with any IO-Link version 1.1-compliant master. The board contains a male M12 connector for connection to a compliant IO-Link master using a standard M12 cable. Connect the MAXREFDES173# to any IO-link master for easy evaluation (for example, the iqLink® USB IO-Link Master with the associated software).


  • IEC 61131-9 Compliant
  • IQ2 Development IO-Link Stack
  • IO-Link Version 1.1 Compliant
  • Measures Temperature from -40°C to +85°C with ±1.75°C Accuracy

User Manual and source code is available on request.