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I am having a difficult time figuring out how to prototype in the IOT realm. This mainly stems from the accessibility of components and modules; and the size of them. Here is what I have done so far.

  • Identified chipsets that fit my use case such as qualcomm 9205/9206.
  • Found modules that I think have that chipset in them (at this point the chip has become physically too big) Quectel EP06
  • searched for prototyping boards that the module will fit into.

So my problem is that the Quectel EP06 is too big and I dont know my next step after this POC prototype. Essentially I need to fit the final solution into less than 18mm by 18mm. All the SOC needs is low power LTE and global positioning like GNSS.

I've searched online and the only chip that looks like it will work is the qualcomm 920x series.

Does anyone know the process to prototype with a chip like this? Am I going down the right path here? I am new relatively new to prototyping and very new to working with SOC type chips.

Thanks

Adam

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  • Are you trying to build a GPS module? And do you have any specification rather than that of the size of the board/ module
    – Maaz Sk
    May 11 at 14:55
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    yes. gps, low power lte (not 2g or 3g), microcontroller, small battery. May 11 at 15:28
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    Usually you start with development boards which may be larger but integrate everything including easy connections. Then you probably move to SMT modules which are smaller, but may not include things like antenna connectors (though this is highly variable). Then if that's not enough and you have the capabilities you move to your own PCB? You also need to be sure you will have enough volume, some chips are not available in small quantities. Have you checked all the modules linked from the Qualcomm site? Also don't forget you'll need an antenna, possibly antenna connectors and battery connectors
    – jcaron
    May 11 at 22:21
  • @jcaron Thank you, This tells me I am on the right path. The SMT module I have identified is too big and has parts I dont need, so I will need smaller. That is the other part of my question. are the SMT manufactures who I would work with for a smaller SMT implementation. Yes I did check the modules linked from qualcomm, that is how I learned about the SMT modules. Also, I'd like to accept your response as an answer with that added information if you move it. May 12 at 15:57
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    Have you checked the Quectel BG77? 14.9mm × 12.9mm × 1.7mm with LTE Cat M1, LTE Cat NB2 and GNSS. Or the U-Blox ALEX-R5? Not sure if they use the 9205 though. There are probably more, I didn't really check extensively (and I don't know your requirements other than low power 4G and GNSS -- though GNSS and low power seem quite difficult to conciliate).
    – jcaron
    May 12 at 16:10
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There are different possible stages, though the details will vary a lot on what you are trying to achieve, what is on the market, your technical and financial means, expected volume, etc.

  • The easiest solution is to use development boards, which are not always very small, but usually have all sorts of interfaces, connectors and additional stuff which is very useful for prototyping (such as USB interfaces, configuration jumpers, several power sources, test pads, connectors for antennas and batteries and external devices, pins to use on a breadboard, LEDs, etc.), but of course takes space (and adds cost). You can often use those without soldering a thing.

    This allows you to test the functional aspects, software, and so on.

    For some products you can directly re-use such boards, if they meet your constraints.

  • The next possible solution is to use SMT modules. Those have the minimum components to run (in your case the 9205 needs additional components such as the SDR105 front-end, a PMIC...), but more limited physical interfaces. In many cases the only connections are just the solder pads, which may be more or less easy to manipulate (they can be just on the edges or you could have dozens of contacts under the module).

    Many such modules include shielding and have been EMC/RF tested, which can simplify your regulatory approval process.

    In some situations such modules will include an antenna connector (u.FL), a PCB trace antenna, or a ceramic antenna, and associated matching network. All the rest needs to go through the contacts of the module, which means you'll have this soldered onto a PCB which will then have the connectors for whatever your need (antenna, battery...) as well as buttons (reset? factory reset? configuration?), LEDs, and whatnot. Depending on the power source and what is inside the module, you may also need voltage regulators, battery charging circuits, USB ports... Don't forget that you'll need to program the devices initially!

    Of course in this case, you ned to design your own PCB, have it made and assembled (or have the resources to do it yourself), which on every new version means time and money.

  • The final step is just to design your own full PCB onto which you'll have all the components you need and just those you need. In some cases it may be relatively easy, in others significant skills may be needed which you may not need when using an SMT module.

Note that the minimum quantities involved usually increase along the way: dev boards are sold by the unit, modules sometimes require slightly higher quantities, the chips themselves may have very high minimum order quantities (MOQ). 100K pieces to order directly from the manufacturer is common, and for some chips it's the only way to get them (others you can get for any quantity, but the price may be quite different depending on the quantity).

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  • This is incredibly helpful! Thank you for taking the time. May 12 at 16:58

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