I am using the ADuC7060 to convert an analog signal to a digital signal. I am using pins ADC0 and ADC1 for 2 independent readings. The analog signals are in the range 0 - 30 mV. The converted data looks good as long as the chip temperature stays above ~-5 C.
When the chip temperature drops below this point, the readings make a dramatic shift down and remain down while the temperature is below the threshold mentioned. While the readings are in this shifted down stage, they do not correlate to the correct readings. I have observed that the "shifted down" readings are inversely related to the power supply.
As the chip temperature rises to above the threshold, the readings will make another shift to above where the expected readings should be and then a short time later the readings will return to where they are expected to be.
Any help with this issue would be greatly appreciated.
Thank you. PDF
The work temperature for ADuC7060 is -40~125'C. If the part you use is a normal part, it should work well even working in a lower temperature. Have you used more than one ADuC7060 to check this case?
Please provide more information, such as which reference do you use, internal or external. Why did you mention the power supply? Is the power supply stable during your measurement? Do the input signal keep stable when the temperature changes?
Thank you for your reply. Yes, we have been able to test on more that one ADuC7060 with the same result. We are using internal reference of 1.2V
I mentioned the power supply because when the converted data from our pressure sensor (inputs ADC0 and ADC1) makes a shift due to a low temperature, the data is trending inversely with the power supply. For example, if the power supply voltage is dropping such as " \ ", then our data readings will trend inversely such as " / ". If you look closely you can see this result on the chart provided in my previous post. We are reading the voltage of our power supply through ADC4. We are also reading analog temperature signals from 4 different temperature sensors through inputs - ADC6,7,8,9. We have noted that the converted data from the temperature sensors makes no shifts with temperature.We are only seeing the shift for inputs ADC0 and ADC1.