INDUSTRY’S FIRST THERMOCOUPLE-TO-DIGITAL CONVERTERS HAVE INTEGRATED COLD-JUNCTION COMPENSATION
SUNNYVALE, CA-December 4, 2001-Maxim Integrated Products introduces the MAX6674/MAX6675 direct thermocouple-to-digital converters. Both precision ICs convert the output voltage of a type-K thermocouple into a digital code that represents the thermocouple’s temperature. The output data have either 10-bit, 0.125°C resolution (MAX6674) or 12-bit, 0.25°C resolution (MAX6675) and can be read at any time over the simple, read-only serial interface.
Working with thermocouples is normally difficult because of the low output voltages from these sensors and the need to provide cold-junction compensation (which corrects errors caused by the temperatures of the connections between the thermocouple wires and the measurement circuitry). Typical thermocouple interface circuits use numerous components and require offset and gain trims to make them useful. The MAX6674/MAX6675 perform the gain, scaling, cold-junction compensation, and analog-to-digital functions in a single IC, thereby eliminating much of the effort and cost associated with such circuits.
Communication is over a simple, read-only, SPI-compatible serial interface, which can reach speeds up to 4.3MHz.
The MAX6674 accepts type-K thermocouples at temperatures between 0°C and +128°C and has 10-bit (0.125°C/LSB) resolution. The MAX6675 accepts type-K thermocouples at temperatures between 0°C and +1024°C and has 12-bit (0.25°C/LSB) resolution. Both circuits operate from supply voltages between 3.0V and 5.5V and over the industrial temperature range from -20°C to +85°C. They are available in 8-pin SO packages.
Prices start from $3.75 for the MAX6674 and $3.88 for the MAX6675 (1000-up, FOB USA).
each speeds up to 4.3MHz.
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