Anyone who has had to wire up more than one thermocouple knows it’s rarely plug-and-play. Each sensor needs its own amplifier, ADC, and cold-junction compensation, and every connection is another chance for error or drift. By the time you’re done, there’s a stack of components to validate and usually a long calibration step before production can start.
Microchip’s MCP9604 was built with that problem in mind. It handles four thermocouple inputs on a single chip and sends the results out over I²C. Accuracy is around ±1.5 °C, which is good enough for most process-control and industrial monitoring jobs, and it does it without the tangle of separate front-end circuitry.
How It Works
Inside the MCP9604 is everything you’d expect in a well-built thermocouple chain, amplifiers, ADCs, a cold-junction sensor, along with a math engine that uses NIST ITS-90 equations to calculate a precise result. With K-type thermocouples, it reaches ninth-order accuracy, something hard to match with discrete parts unless you invest serious time in calibration.
This single-chip approach has a few nice side effects: the PCB gets cleaner, the bill of materials shrinks, and most of the painful unit-by-unit calibration work can be skipped. Over a production run, that can save days of setup and rework.
Flexible Enough for Real-World Jobs
The part works with eight thermocouple types, including J and K, and covers a range from –200 °C up to +1372 °C. That makes it a good fit for everything from cryogenic storage and food processing to furnace monitoring and HVAC control.
For anyone wanting to try it out, Microchip sells the EV19L27A evaluation board, which lets you connect four thermocouples and watch live readings using free software. It’s a quick way to experiment before committing to a design.
The MCP9604 is available now in a 24-pin, 5 × 5 mm LGA package and costs about $10.56 in 10k-unit quantities.
Learn more and read the original article on www.microchipdirect.com
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