MAX31856

Precision Thermocouple to Digital Converter with Linearization

Simplifies Thermocouple Designs with Integrated Automatic Cold Junction Compensation and Linearization Correction


Please check latest availability status for a specific part variant.

Description

The MAX31856 performs cold-junction compensation and digitizes the signal from any type of thermocouple. The output data is formatted in degrees Celsius. This converter resolves temperatures to 0.0078125°C, allows readings as high as +1800°C and as low as -210°C (depending on thermocouple type), and exhibits thermocouple voltage measurement accuracy of ±0.15%. The thermocouple inputs are protected against overvoltage conditions up to ±45V.

A lookup table (LUT) stores linearity correction data for several types of thermocouples (K, J, N, R, S, T, E, and B). Line frequency filtering of 50Hz and 60Hz is included, as is thermocouple fault detection. A SPI-compatible interface allows selection of thermocouple type and setup of the conversion and fault detection processes.

MAX31856: Block Diagram MAX31856: Block Diagram Enlarge+

Key Features

  • Provides High-Accuracy Thermocouple Temperature Readings
    • Includes Automatic Linearization Correction for 8 Thermocouple Types
    • ±0.15% (max, -20°C to +85°C) Thermocouple Full-Scale and Linearity Error
    • 19-Bit, 0.0078125°C Thermocouple Temperature Resolution
  • Internal Cold-Junction Compensation Minimizes System Components
    • ±0.7°C (max, -20°C to +85°C) Cold-Junction Accuracy
  • ±45V Input Protection Provides Robust System Performance
  • Simplifies System Fault Management and Troubleshooting
    • Detects Open Thermocouples
    • Over- and Undertemperature Fault Detection
  • 50Hz/60Hz Noise Rejection Filtering Improves System Performance
  • 14-Pin TSSOP Package

Applications/Uses

  • Industrial Equipment
  • Industrial Ovens, Furnaces, and Environmental Chambers
  • Temperature Controllers
Part NumberSensor TypeFunctionsInterfaceChannelsAccuracy
(±°C)
Parasite Pwr.Temp. Resolution
(bits)
Oper. Temp.
(°C)
Package/PinsBudgetary
Price
See Notes
MAX31856 RemoteThermocouple-to-Digital Converter3-Wire/SPIOne1.5No19-55 to +125
TSSOP/14
$3.80 @1k
See All Temperature Sensors (113)
Pricing Notes:
This pricing is BUDGETARY, for comparing similar parts. Prices are in U.S. dollars and subject to change. Quantity pricing may vary substantially and international prices may differ due to local duties, taxes, fees, and exchange rates. For volume-specific and version-specific prices and delivery, please see the price and availability page or contact an authorized distributor.


MAX31856EVSYS: Evaluation System for MAX31856

Technical Documents

App Note 6550 The Basics of Thermocouples
App Note 6508 How to Implement a 4-20mA Transmitter with the MAX12900
Tutorial 6500 Temperature Sensor Tutorial

Quality and Environmental Data

Product Reliability Reports: MAX31856.pdf 
Lead-Free Package Tin (Sn) Whisker Reports
Device   Fab Process   Technology   Sample size   Rejects   FIT at 25°C   FIT at 55°C  

Note : The failure rates are summarized by technology and mapped to the associated material part numbers. The failure rates are highly dependent on the number of units tested.

Quality Management System >
Environmental Management System >

Related Resources


MAX22195
High-Speed, Octal, Industrial Digital Input with Parallel Output

  • High-Speed, Industrial Digital Inputs
  • High Integration Reduces BOM Count and Board Space
  • Low Power and Low Heat Dissipation

MAX30002
Ultra-Low-Power, Single-Channel Integrated Bioimpedance (BioZ) AFE

  • BioZ AFE with High Resolution Data Converter
  • High AC Dynamic Range of 90mVP-P Will Help Prevent Saturation in the Presence of Motion/Direct Electrode Hits
  • Longer Battery Life Compared to Competing Solutions

MAX32664
Ultra-Low Power Biometric Sensor Hub

  • Biometric Sensor Hub Solution Enables Faster Time to Market
  • Finger-Based (Version A) Algorithms Measure
  • Both Raw and Processed Data Are Available

MAX22190
Octal Industrial Digital Input with Diagnostics

  • High Integration Reduces BOM Count and Board Space
  • Reduced Power and Heat Dissipation
  • Fault Tolerant with Built-In Diagnostics

MAX22191
Parasitically Powered Digital Input

  • High Integration for Flexible Circuit Designs
  • Reduced Power and Heat Dissipation
  • Robust Design

MAXREFDES220
MAXREFDES220#: Finger Heart Rate and Pulse Oximeter Smart Sensor with Digital Signal Processing