Thermocouple to digital converters

4 September 2013 Analogue, Mixed Signal, LSI

Maxim’s new MAX31850 and MAX31851 are cold-junction compensated, 1-Wire converters achieving ±2,0°C accuracy (not including sensor nonlinearity) while integrating all of the functions required for a complete thermocouple-to-digital solution.

The 1-Wire interface allows multiple sensor locations to communicate and draw power over a single data line, greatly simplifying wiring requirements. Designers can use the devices instead of multiple discrete components for accurate temperature measurement in medical, industrial and solar applications.

Because thermocouple output voltages are small and cold-junction compensation is needed to achieve accurate results, the digitisation of thermocouple signals can be a challenge. To this end, the MAX31850/MAX31851 integrate a discrete analog-to-digital converter (ADC), a highly accurate reference and a temperature sensor for cold-junction compensation.

The versatile converters operate with several types of thermocouples (K, J, N, T and E for the MAX31850; R and S for the MAX31851) and are able to identify open or shorted thermocouples that could result in erroneous temperature readings or system faults. A microcontroller can read the fault status at any time.

The chips are available in a 10-pin, exposed-pad TDFN package measuring 3 x 4 x 0,75 mm, and are specified over the -40°C to +125°C temperature range.

For more information contact Erich Nast, Avnet Kopp, +27 (0)11 319 8600, [email protected], www.avnet.co.za.

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