MAX31865 PT100 module

The MAX31865 is a high-accuracy digital converter specifically designed to interface with platinum RTDs such as the PT100 and PT1000. It simplifies temperature sensing by converting resistance to digital output via SPI, making it ideal for use in industrial, scientific, and embedded applications. With support for 2-, 3-, and 4-wire RTD configurations, integrated fault detection, and a 15-bit ADC, this module provides precise and reliable temperature readings.

Features

• Compatible with PT100 and PT1000 RTDs

• High-resolution 15-bit delta-sigma ADC

• SPI digital interface for easy microcontroller integration

• Supports 2-wire, 3-wire, and 4-wire RTD setups

• Accurate and stable temperature measurement

• Built-in fault detection: open circuit, short, and out-of-range

• Fast conversion time (as low as 21 ms)

• ±45V input protection on RTD pins

• Compact design for embedded systems

• Low component count for simple integration

Specifications

• Sensor Compatibility: PT100 and PT1000 platinum RTDs

• ADC Resolution: 15-bit delta-sigma

• Temperature Resolution: 0.03125°C (subject to RTD accuracy)

• Total Accuracy: Up to ±0.5°C

• Communication Interface: SPI

• RTD Wiring Support: 2-wire, 3-wire, and 4-wire

• Conversion Time: As fast as 21 ms per reading

• Input Protection: ±45V overvoltage tolerance

• Operating Voltage: Typically 3.3V or 5V

• Fault Detection: Open, short, and out-of-range detection

• Package Types: Available in 20-pin TQFN and SSOP formats

Applications

• Industrial temperature monitoring and control

• Precision thermal sensing in laboratory equipment

• HVAC and refrigeration system feedback

• Embedded systems with high-temperature accuracy requirements

• Food processing and pharmaceutical temperature logging

• Power electronics thermal management

• Environmental control systems