RTOS/CC3220MODA: Cheap temperature sensing solution for CC3220MODA

Hi Jan,
Please find my needs below.

- temperature range -30°C ~ 90°C
- expected accuracy - not a major concern as I am trying to find whether it crosses a threshold.
- where will be sensor mounted (on the PCB, on cable probe; IPx for cable probe) - PCB mounted
- expected resolution - 10 or 20mV per °C (not much worried about the accuracy as stated above)
- response time - per second or more
- long term stability - should be reliable for at least 10 years.

All I am trying to find out is whether my board overheats (i.e whether it goes above 80°C)

Regards,
Zac

Hi Zac,

For this purpose will best fit some low cost digital sensor. With analogue sensor you will need do calibration in manufacturing and this will cost much more. Also you will need to use ADC in CC3220, which I not personally like.

There is many similar sensors on the market. Even TI have a few low cost sensors in the portfolio - www.ti.com/.../products.html

Jan

Hi Zac,

Depending of design of your analogue RTD circuits it may be required do calibration during manufacturing for this sensor. In this topic is important what accuracy of sensor do you expect.

TMP75 looks like decent sensor for your purpose. I am not aware about driver/example codes for this sensor. But according datasheet it looks that reading values from sensor is easy.

Jan

Dear Jan,
Accuracy is not an important factor for my purpose rather I am looking for a cheaper solution with long term reliability. My purpose is to find whether my MCU (CC3220) overheats beyond an acceptable limit(above 80°C) and if it happens I would shutdown the system to avoid damage. A 10% error in the reading should not be a major concern as my usual operating temperature is below 50°C.
Looking at TI products, I could also find analog IC based sensor which has better accuracy(unlike thermistors) within a temperature range of -40 to 150°C. They also seems to be very much cheaper. Few examples are TMP235, LMT85 from TI
Do you think these sensor would require individual calibration in manufacturing ?

Regards,
Zac

Hi Zac,

I have no experiences with this chips. In my designs I use high precision digital thermometers or Pt1000 with 16/24bit external ADCs.

But it looks that both chips could be useful for your purpose and calibration during manufacturing should not be required. But be aware that ADC in CC3220 can work at range 0 to 1.4V only. More than 1.8V can damage ADC input.

Jan

Hi Zac,

OK, it looks like reasonable solution.

Jan