MAX31856

Precision Thermocouple to Digital Converter with Linearization

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


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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.

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.

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