# MAX31865 Temperature Sensor Module, PT100 Sensor, 3-5V

> MAX31865 RTD-to-digital converter module for PT100 sensors, 3-5V supply, SPI interface (CLK, SDO, SDI, CS). Internal 15-bit ADC, 0.03125°C resolution, ±0.5°C accuracy, maximum conversion time 21 ms. Measurement range -200~850°C, installed reference resistor 430Ω for PT100. Automatic broken wire/short circuit detection, ±45V input protection. Compatible with Arduino, ESP32, STM32, Raspberry Pi.

- Page: https://sigmanortec.ro/en/max31865-temperature-sensor-module-pt100-sensor-3-5v
- Price: 57.41 RON
- Availability: In stock; 1-2 zile
- Reference: 88256 · EAN: 5947936582062
- Category: Mechatronics and IoT > Sensors and Modules > Temperature and Environmental Sensors
- Specifications: Sensor type: PT100; Main IC: MAX31865; Supply voltage: 3 - 5 V
- Updated: 2026-09-14
- Shop: [Sigmanortec.ro](https://sigmanortec.ro/en/llms.txt)
- Prices: RON, VAT included; prices and stock as of 2026-10-22 03:00 (Europe/Bucharest)

## Description

Precision converter for temperature measurement with a PT100 sensor, ideal for industrial and laboratory projects, communicates quickly via SPI with microcontrollers such as Arduino or Raspberry Pi. It offers a 15-bit ADC with fine 0.03125°C resolution, accuracy up to ±0.5°C, conversion time of up to 21 ms, and automatic detection of broken cable or short circuit. Power supply 3-5V.
The MAX31865 module is a precision RTD-to-digital converter designed for connecting platinum resistance temperature sensors (PT100 or PT1000) to microcontrollers via the SPI interface. Based on the MAX31865 integrated circuit from Analog Devices, the module fully handles sensor excitation, signal amplification, and analog-to-digital conversion, eliminating the need for any additional external circuitry.
It is recommended for industrial applications, measurement laboratories, and any system that requires precision temperature measurements in the -200 ~ 850°C range.
Among its main features are a 15-bit internal ADC with a resolution of 0.03125°C and an accuracy of ±0.5°C, a maximum conversion time of 21 ms, and input protection of up to ±45V against accidental voltages.
The module includes automatic wiring fault detection, signaling both open-circuit and sensor short-circuit conditions. A 430Ω reference resistor is factory-installed on the board, calibrated for PT100 sensors. For use with PT1000 sensors, the reference resistor must be manually replaced with a 4300Ω one before operation.
The module is powered by 3.3 or 5 VDC and is compatible with Arduino, ESP32, STM32, Raspberry Pi, and any other microcontroller or single-board computer with an available SPI interface. The Adafruit MAX31865 library is available for Arduino IDE, ESP-IDF, and MicroPython, simplifying integration into your project.
Specifications:
Chip: MAX31865
Supply voltage: 3.0 - 5.5 VDC
Interface: SPI (CLK, SDO, SDI, CS)
ADC resolution: 15 bits
Temperature resolution: 0.03125°C
Accuracy: ±0.5°C (max)
Conversion time: 21 ms (max)
Measurement range: -200 ~ 850°C
Installed reference resistor: 430Ω (for PT100)
Reference resistor for PT1000: 4300Ω (requires manual replacement)
Input protection: ±45V
Error detection: open circuit, short circuit
Dimensions: 25.6 x 28.3 mm
Layout and pinout:
Pin
Function
VIN
3.3 or 5 VDC power supply
GND
Common ground
CLK
SPI Clock
SDO
SPI Data Output (MISO)
SDI
SPI Data Input (MOSI)
CS
SPI Chip Select (active LOW)
RDY
Data Ready, optional signal, indicates conversion completion
FORCE+
RTD sensor excitation terminal (+)
FORCE-
RTD sensor excitation terminal (-)
RTDIN+
Sensor voltage measurement terminal (+)
RTDIN-
Sensor voltage measurement terminal (-)
Usage:
Connect the PT100 or PT1000 sensor to the module’s RTD terminals (FORCE+, FORCE-, RTDIN+, RTDIN-), following the correct wiring configuration: 2-wire, 3-wire, or 4-wire.
Power the module with 3.3 or 5 VDC through the VIN and GND pins.
Connect the SPI interface to the microcontroller: CLK, SDO (MISO), SDI (MOSI), and CS.
The RDY pin is optional and can be connected to a microcontroller interrupt pin to detect conversion completion without polling.
Install the Adafruit MAX31865 library from the Arduino IDE Library Manager or via pip/idf depending on the platform.
In the code, specify the Rref value corresponding to the sensor used: 430.0 for PT100 or 4300.0 for PT1000.
Specify the sensor’s nominal resistance at 0°C: 100.0 for PT100 or 1000.0 for PT1000.
The library automatically calculates temperature according to the ITS-90 curve, based on the ratio between the sensor resistance and Rref.
Check the module’s error register in your application code to detect possible wiring issues or sensor faults.
Dimensions diagram:
Datasheet:
https://www.analog.com/media/en/technical-documentation/data-sheets/max31865.pdf
Package contents:
1 x PT100 sensor
1 x MAX31865 converter module for PT100 / PT1000 sensors