LDC1314DIAL-EVM: No Feedback

Hi Tobias,

I do have a board on order and will be able to test this in the next few days when I receive it.  Sorry for the delay.  

The LDC1314 device has an operating temperature range from -40C to 125C.  If using the internal oscillator, there is a temperature coeficient of -13ppm/°C.  This should not cause much variation, and the dial design uses an external crystal oscillator, so this is likely not an issue anyway.  It is possible that some other component in the design is susceptible to temperature change.  I will let you know what I find.   

Tobias,

I have received the board and initial room temperature testing looks okay.  I tried placing the board on my warm laptop to raise the temp a few degrees, but I haven't seen any issues yet.  I will take it into the lab this afternoon and test it in a temperature chamber and report back with results.

Update: I am able to see the issue when I bring the board to around 45C.  It seems like the issue is stemming from the connected MSP430 or the oscillator used for the MSP430.  If I monitor the SCL pin , I see a clean 350kHz clock signal.  When the jumpy behaviour is seen, I see this signal go to a much lower frequency and the pulses are not generated properly created erroneous I2C communication.  As this is a signal generated by the MSP430, it seems that the issue is on that side and not the LDC.  I need to dig further to understand which oscillator may be failing on the board, but at the moment, I am not able to capture a good crystal signal directly from the oscilloscope.  I will continue looking into this and let you know what I can capture.