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Cold-Junction Compensated, 1-Wire Thermocouple-to-Digital Converters

Accurate 1-Wire Thermocouple-to-Digital Converter ICs Ease Design Effort and Lower System Cost

Product Details

The MAX31850/MAX31851 cold-junction compensated, 1-Wire® thermocouple-to-digital converters perform cold-junction compensation and digitize the signal from a K-, J-, N-, T-, S-, R-, or E-type thermocouple. The converters resolve temperatures to 0.25°C, allow readings as high as +1768°C and as low as -270°C, and exhibit thermocouple accuracy of 8 LSBs (2°C) for temperatures ranging from -200°C to +700°C.

Communication with the master microcontroller is over a 1-Wire bus that by definition requires only one data line (and ground) for communication. Operating power can be obtained directly from the data line (“parasite power”), eliminating the need for an external power supply.

Each device has a unique 64-bit serial code, which allows multiple units to function on the same 1-Wire bus. Therefore, it is simple to use one microcontroller (the master device) to monitor temperature from many thermocouples distributed over a large area.

Four location address inputs simplify mapping of individual units to specific locations.

Key Features

  • Integration Reduces Design Time and Lowers System Cost
    • 14-Bit, 0.25°C Resolution
    • Integrated Cold-Junction Compensation
    • Available for Multiple Thermocouples Types: Supports K-, J-, N-, T-, and E-Type (MAX31850); S- and R-Type (MAX31851)
    • Detects Thermocouple Shorts to GND or VDD
    • Detects Open Thermocouple
  • 1-Wire Multiddrop Capability Simplifies Multisensor Systems
    • 1-Wire Interface (Read-Only); Power Can Be Obtained from Interface (Parasite-Powered Mode)

Applications/Uses

  • Appliances
  • HVAC
  • Industrial
  • Medical
Parametric specs for All Temperature Sensors
Sensor Type Remote
# Channels One
Interface 1-Wire
Functions Thermocouple-to-Digital Converter
Accuracy (±°C) 2
Parasite Pwr. Yes
Temp. Resolution (bits) 14
Oper. Temp. (°C) -40 to +125
Package/Pins TDFN/10
Budgetary
Price (See Notes)
$3.26 @1k
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Simplified Block Diagram

MAX31850, MAX31851: Block Diagram MAX31850, MAX31851: Block Diagram Zoom icon

Technical Docs

Design & Development

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Description

The MAX31850/MAX31851 evaluation kit (EV kit) provides the hardware and software graphical user interface (GUI) necessary to evaluate the MAX31850/MAX31851 cold-junction compensated, 1-Wire® thermocouple-to-digital converter.
The EV kit comes with a MAX31850KATB+ soldered to the PCB. This is the K-type thermocouple version of the device. Other thermocouple types can be evaluated by procuring the desired thermocouple, thermocouple socket, and corresponding MAX31850 or MAX31851. Contact the factory for free samples of the devices to match your desired thermocouple type. See the Evaluating Other Thermocouple Types section in the full data sheet for part numbers and additional information regarding other thermocouple types.

View Details

Features

  • Includes Everything Needed to Evaluate a MAX31850K with a K-Type Thermocouple
  • EV Kit Hardware is USB Powered (USB Cable Included)
  • Windows XP®- and Windows® 7-Compatible Operating System Software
  • USB HID Interface
  • Second Channel Allows Easy Evaluation of Other Thermocouple Types
  • Fully Assembled and Tested on Proven PCB Layout
  • RoHS Compliant

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Support & Training

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Parameters

Parametric specs for All Temperature Sensors
Sensor Type Remote
# Channels One
Interface 1-Wire
Functions Thermocouple-to-Digital Converter
Accuracy (±°C) 2
Parasite Pwr. Yes
Temp. Resolution (bits) 14
Oper. Temp. (°C) -40 to +125
Package/Pins TDFN/10
Budgetary
Price (See Notes)
$3.26 @1k

Key Features

  • Integration Reduces Design Time and Lowers System Cost
    • 14-Bit, 0.25°C Resolution
    • Integrated Cold-Junction Compensation
    • Available for Multiple Thermocouples Types: Supports K-, J-, N-, T-, and E-Type (MAX31850); S- and R-Type (MAX31851)
    • Detects Thermocouple Shorts to GND or VDD
    • Detects Open Thermocouple
  • 1-Wire Multiddrop Capability Simplifies Multisensor Systems
    • 1-Wire Interface (Read-Only); Power Can Be Obtained from Interface (Parasite-Powered Mode)

Applications/Uses

  • Appliances
  • HVAC
  • Industrial
  • Medical

Description

The MAX31850/MAX31851 cold-junction compensated, 1-Wire® thermocouple-to-digital converters perform cold-junction compensation and digitize the signal from a K-, J-, N-, T-, S-, R-, or E-type thermocouple. The converters resolve temperatures to 0.25°C, allow readings as high as +1768°C and as low as -270°C, and exhibit thermocouple accuracy of 8 LSBs (2°C) for temperatures ranging from -200°C to +700°C.

Communication with the master microcontroller is over a 1-Wire bus that by definition requires only one data line (and ground) for communication. Operating power can be obtained directly from the data line (“parasite power”), eliminating the need for an external power supply.

Each device has a unique 64-bit serial code, which allows multiple units to function on the same 1-Wire bus. Therefore, it is simple to use one microcontroller (the master device) to monitor temperature from many thermocouples distributed over a large area.

Four location address inputs simplify mapping of individual units to specific locations.

Simplified Block Diagram

MAX31850, MAX31851: Block Diagram MAX31850, MAX31851: Block Diagram Zoom icon

Technical Docs

Support & Training

Search our knowledge base for answers to your technical questions.

Filtered Search

Our dedicated team of Applications Engineers are also available to answer your technical questions. Visit our support portal.