The MAX31855 is a cold-junction compensated thermocouple-to-digital converter from Maxim Integrated Products. It supports K, J, N, T, S, R, and E type thermocouples. The converter has a 14-bit, 0.25NC resolution SPI-compatible read-only interface. It can measure temperatures from -270NC to +1800NC with an accuracy of ±2NC for K-type thermocouples. The MAX31855 is suitable for use in industrial, home appliance, and automotive applications.
The MAX31855 is a cold‑junction compensated thermocouple‑to‑digital converter that digitizes signals from K, J, N, T, S, R, or E‑type thermocouples. It provides a signed 14‑bit SPI‑compatible output with 0.25 °C resolution and includes fault detection for open or shorted thermocouples.
The device operates from –40 °C to +125 °C, requires a supply voltage of –0.3 V to +4.0 V, and consumes up to 470.6 mW at +70 °C. It is supplied in an 8‑lead SO package and is intended for use with an external microcontroller via a simple SPI‑compatible interface.
| Supply Voltage Range (VCC to GND) | -0.3 V to +4.0 V |
|---|---|
| Operating Temperature Range | -40 °C to +125 °C |
| Thermocouple Temperature Resolution | 0.25 °C |
| Thermocouple Accuracy | ±2 °C |
The MAX31855 provides a thermocouple temperature resolution of 0.25 °C.
It detects a short to VCC, a short to GND, and an open thermocouple condition.
The device operates with a supply voltage from –0.3 V to +4.0 V.