tmp116: how to put a tmp116 into a probe

Hi rifo,

TMP116 is a great device whether for probe to measure appliance or medical applications. I am currently working on the apps note for the TMP116 probe. I think it will probably publish sometimes next week. It is very strange to me that you want to minimize the thermal response time. Most customers want to build a probe with the fast thermal response time. I will provide you the link as soon as it get to TI.com.

Aaron

Rifo

Hello Aaron,

Has TI published the app note for putting tmp116 in a probe? Thanks a lot for your help

have a nice day

rifo

Hi Rifo,

Sorry for the delayed. We are still working on getting the apps note publish to TI.com. Attached is the preliminary final draft. Let me know if you have any question.

Thermal Response_SNIA021_15Nov2017.pdf

Aaron

Hey Aaron,

This is absolutely great stuff. I have learned a lot from this document. I've got three questions. I would be happy
if you can guide me about them.

My goal with TMP 116 is to achieve a similar performance with a Testo-106
www.testo.com/.../0560-1063

Testo-106 says that it has a NTC temperature probe and 10 seconds of t99 thermal response in moving liquid.

When I check the response times of TMP 116, I see that

Probe P8 with Layout L4 has the best response.

Can you please give more detail about P8 ? I wasn't able to find information about this?
Can you also give top view of L4 ? From the figure, it seems like the pads are connected to thermal Pad

Also, does NTCs in general provide better response times than TMP116, Testo-106 claims to achieve t99 in 10 seconds
which seems to be better compared to TMP 116 probes but again maybe the liquid is different?

thanks a lot
rifo

Hi Rifo,

I'm glad that you found it useful. It is possible that Testo-106 has 10 seconds thermal response time because it has a smaller diameter, I think the thickness of probe is thinner than the one I have in the apps note, and the NTC is in smaller package. With the current design of Testo-106, TMP116 might be too big to insert inside the shaft. You might need to increase the diameter of the probe.

You are correct that P8 has the thermal pad connected to the pad. I expected L2 has the faster response time because it has less thermal mass. It could be that I applied too much of the thermal epoxy.

It is possible to get a faster response time of the TMP116 if we used the layout L2 with smaller and thinner probe.

TMP116 Mini Board Top View.pdf

Let me know if you need help.

Aaron

Hello Aaron,

Thanks a lot for your answer. I will then try to build a probe with the L2 layout and a smaller, thinner probe.

Is it also possible to give information about how to get the probe? Did you purchase it or build it?

Thanks Aaron,

I don't live in the States so I will find a suitable alternative. Can you also give a little bit more info about how you applied the thermal epoxy and also (if possible) a link to the one that you used.

Did you first put the probe and then apply the epoxy or is it the other way around?

thanks
rifo

Hi Rifo,

Sorry to hear about that. Any machinery shop can make the probe as long as you provide a desired specs and dimension. Attached is the epoxy datasheet that I used when I assembled the probe. You should consider the highly thermal conductive epoxy Duralco 132. Epoxy usually comes with 2 materials and needs to mix the ratio before applying. It requires a ratio of two materials mix up unless you want to use silicone based.  Silicone does not require mixing ratio , but the cost is much higher. You can get the cure time faster by putting inside the oven at 70°C.

First, I soldered the wire on my miniature board then applied a mixed thin layer of the epoxy at the copper plane sensing area afterward quickly insert into the tube with a small strip of form to suppress the board fitly against the probe's wall.

5710.13 128 134 135 133.pdf

4405.12 132 132IP.pdf

Hope this helps. Let me know if you have further question.

Aaron

Hi Aaron:
I saw the small probe board of TMP116 without any capacitor placed, is that all right?

Hi,

Yes you are correct. Since I am doing thermal response, it is not necessary, but you might want to place a cap 0201 across the V+ and GND.

Aaron