Ambient Temperature Sensor

Dear Piyush - 

What size are you thinking you need? 

What accuracy range do you require? 

The TMP117 is the most accurate digital device. (+/-0.1 degree Celsius) and it can most certainly measure ambient temperature, but your mechanical placement will be key to get the results you want. If you want to cover any gradient, you would need multiple sensors placed in strategic locations. 

Backing up from there, you are right, there are many choices, but you will need to look at your requirements on input voltage, accuracy, temp range being covered, interface and size of the board you are making to filter them. 

Do you need Q100? 

If so, here are the digital and analog temp sensing parts that are rated for automotive - 

Hello Josh 

Thanks for your quick feedback. My device will run from a rechargeable battery, but in order to reduce the power consumption of the device i am planning to use a buck regulator and drop the voltage to 2.1V or similar to that range. i will have the CC2650 controller for interfacing the temperature sensor. So my preference is to have a I2C based digital temperature sensor. My temperature range is most probably the room temperature range. 

I am sorry but i didn't understood what do you mean by Q100?

The reason i am skeptical about the TMP117 is because my device will be enclosed in a plastic casing. As per current plans, we are planning to expose the digital temperature sensor by providing some vents for the ambient airflow. Do you think still the TMP117 should be able to provide the ambient temperature. Please let me have your feedback. 

Regards

Piyush Saxena

Dear Piyush - 

Q100 is an automotive qualification standard - formally known as AEC-100. You said this was going in a vehicle, so this is why I asked about this. 

I think your concern is valid regardless of any temp sensor you pick, but the TMP117 would work as well or better as any other. Are you thinking you need a probe of some type? do you have a mechanical drawing of that enclosure already so we can look at it and comment further?

Hi Josh,

I appreciate your participation, unfortunately we are still at the stage where we are finalizing the architecture and various parts of the whole system. So unfortunately i don't have the designs to share with you. Since you believe as well as suggest that TMP117 should also serve my purpose hence i believe that it should be good to go ahead with it. 

I would like to know that does TMP117 qualifies for Q100 automotive qualification standard?

Also just for my understanding, in case i am fine with the TMP75 accuracy so do you think that in my case a bigger body of the IC shall help me to get better ambient temperature sensing considering the enclosed casing with the vent. Also does TMP75 also qualifies with the Q100 automotive quality standards?

Thanks.