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


Accurate 1-Wire thermocouple-to-digital converter ICs ease design effort and lower system cost

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.

MAX3185x Thermocouple to Digital Converter
Features
  • Cold-junction compensation
  • 14-bit, 0.25°C resolution
  • Versions available for multiple thermocouples types: MAX31850 supports K-, J-, N-, T-, and E-types; MAX31851 supports S- and R-types (see table 1 in the full data sheet)
  • 1-wire interface (read-only); power can be obtained from interface (parasite-powered mode)
  • Detects thermocouple shorts to GND or VDD
  • Detects open thermocouple

MAX31850/MAX31851

Manufacturer Part Number Description Available Quantity Datasheets
MAX31850EATB+ IC CONV THRMCPLE-DIG E TYPE TDFN 18
MAX31850EVKIT# EVAL KIT FOR MAX31850 3
MAX31850JATB+ IC CONV THRMCPLE-DIG J TYPE TDFN 2159
MAX31850KATB+ IC CONV THRMCPLE-DIG K TYPE TDFN 0
MAX31850NATB+ IC CONV THRMCPLE-DIG N TYPE TDFN 20
MAX31850TATB+ IC CONV THRMCPLE-DIG T TYPE TDFN 2387
MAX31851RATB+ 1-WIRE THRMOCPLE TO DIG CONV 17
MAX31851SATB+ 1-WIRE THRMOCPLE TO DIG CONV 16