TI E2E Community
Temperature Sensors Forum
TMP006 - PCB design rules for prototypes
I'm looking to build a breakout board for the TMP006, to test the part for suitability in my target application. I have access to PCB production equipment, and would rather use this (at least during early prototyping) than have a set of boards manufactured and be subject to my supplier's 4-week turnaround on bare-PCB orders (or a significantly higher price to reduce the delivery time frame).
This, however imposes some restrictions - my minimum drill size for in-house prototype boards is 0.6mm, and the manufacturing equipment is limited to 6mil track width and 6mil spacing. I can produce double sided boards but WITHOUT through-plating or solder-masking.Ideally I'd prefer to use a 0.8mm drill size, as this would allow me to use Harwin-type solid track pins (Harwin P/N T1559F46) to form the vias, however bare-wire and a 0.6mm drill is another option.
Now onto my questions: How can I limit the effect this will have on the TMP006? What effects can I expect from varying the PCB layout in this manner? What is the best way to handle the increased amount of space required for the vias? Should I increase the area of the internal copper fill, extend the tracks out into the isolation area, or some combination of the two?
Alternatively, could the TMP006 be used if it were soldered into an IC socket with thin wire and operated suspended in air (instead of mounted on a PCB)?
The TMP006 layout does have some room for modification. In general, most customers want to be provided with as small of a layout as possible so our recommended layout in the User's Guide was designed with that in mind.
Your limitation of 6 mil track width and spacing are sufficient for the center portion of the layout (Fig. 5 on the TMP006 User's Guide). Follow those recommendations exactly.
There should be no problem with an 0.8mm (31.5 mil) drill hole for the vias. Allow a decently-large annular ring (1.2mm to 1.6mm diameter) and increase the size of the ground copper area to accommodate the larger via size. Scale the size of the isolation area so that the ratio of the size of the isolation area and copper area is roughly the same. The layout in the user's guide follows a ratio of 1.67:1.
You should get accurate performance if following these guidelines. Feel free to post a screenshot of your layout or send Gerber files if you would like me to review them further. You can message me directly through the E2E site if you would rather not share your files/screenshots with the forum.
I would definitely not place the TMP006 in a socket and/or suspend it in air. The device must be tightly thermally coupled to a PCB in order to achieve accurate performance.
Ian WilliamsLinear Applications EngineerPrecision Analog and Sensing Products
Thanks for the very informative reply. The CAM files (Gerbers) are in a zip file in my Files area, and follow EAGLE's filename conventions:
I'm not sure if you'll be able to see these as-is -- if not, please send me a Friend Request and they should become visible.
I downloaded the Gerber files and will take a look soon.
Hello again Philip,
Your Gerber files look great. I don't foresee any issues with this layout.
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