We are currently designing a "conditioning" module that takes a couple of sensors (T°, Pressure but also via digital bus) and repeats over CAN / also outputs them in nice and clean analog signals (0-5V) when needed.
Problem is : we are trying to find an analog (the detail is imporant) thermocouple conditioning chip that carries a serious Cold Junction Compensation mechanism.
N.B : we've obviously found the AD595/59x series but they only specify (and guarantee, we've contacted them) for Cold Junction Temperatures above freezing point (0°C). They might work below but we have no firsthand experience with them out of the datasheet so we can't legitimately integrate them.
The other option being to use a Tk-to-digital but we want to avoid that for various reasons.
- Is our only option to use discrete Op-Amps with a CJC mechanism based on discretes?
- Have any of you any experience on using these integrated-CJC out of specs? the +50°C is fine by us but we need to go below 0°C. What we are really asking ourselves is : what happens when we go below the minimum (0°) ? Does the CJC stop working altogether or does it compensate based on a temperature of 0°?
Thanks for the help,