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Using TIVA Launchpad TM4C123G with a *REALLY* Small Chip

Bob Jennings
Intellectual 360 points

Hi guys.  Apologies upfront for my lack of knowledge in electronics.  I'm a very competent software engineer, but never worked with much hardware or electronics.  I've been having a ton of fun with my Tiva Launchpad (TM4C123G) lately, learning how to program ARM Cortex chips to do cool things.  I have it working with typical external discrete parts (buttons, potentiometers, resistors) via bread boards but now I want to interface it with an 8 bit DAC chip.  This is the actual chip.

Problem: This chip is literally 3 x 1 millimeters.  I've managed to find (what I *think* is called) a breakout board that fits the chip - something like this - but the pins on the chip are soooo small that I'm very hesitant to try and solder it to the board.  Can anyone tell me what the typical, correct approach to getting a chip of this size on a breakout board?

Much thanks in advance,

Bob 

  • 0
    TI__Guru**** 244400 points
    Hello Bob

    We all begin some place. First and foremost get a good flux. Apply it on the breakout board pad landings. Then put the device on the pad landings. Tack the corner pins to hold the device in place with a solder and solder metal. The trick to apply is to make sure that the solder touches the pin and the pad landing junction and applying the solder metal from the pin.
  • 0
    Guru 47900 points

    Poster, "ID correct approach to getting a chip of this size on a breakout board?"

    Ans: DON'T!    Moving from HW novice to fine pitch, IC soldering maven, proves unlikely.    And - even if you mount it as Amit suggests - you must "harvest the two analog outputs - and provide connections back to your MCU.   Not fun - and a far easier approach is available!

    How did you wind up w/that SO small device?
    MAX548ACPA (electrically identical) is available & stocked in an IMMENSELY EASIER TO HANDLE/SOLDER "8 pin DIP" (standard) package.

    It seems pointless to use so small a device when a (properly) sized, identical device is available.

    If you absolutely must use so small a device I'd design a pcb expressly for it - and have a "pro" reflow solder it for you. (assumes there exists NO breakout board for that device.

  • 0 in reply to cb1
    Guru 11940 points

    I have seen people soldering all pins (of one row) at once, and remove the excess solder with desoldering braid. But this were "professionals", that did such things on a daily basis.

    In general, I would second cb1's suggestions. Either have a "pro" do it for you, or get a breakout board for that chip. I had been soldering fine-pitch ICs in the past, with proper equipment.

    I can't do this at home for the lack of equipment, so I avoid such situations. And, as cb1 mentioned, I go for DIP in this case...

  • 0 in reply to f. m.
    Guru 11940 points
    BTW, if you want to see ** really small ** chips, check out BGA packages.
    Soldering by hand stops here ...
  • 0 in reply to f. m.
    TI__Guru**** 244400 points
    Hello f.m.

    I would disagree. "pro" starts a novice. I still use a standard solder tip and some flux to solder down 128 pin packages without access to specialized equipment.
  • 0 in reply to Amit Ashara
    Guru 11940 points

    I still use a standard solder tip and some flux to solder down 128 pin packages without access to specialized equipment.

    If one interprets "not specialized equipment" as a normal "industrial quality" soldering iron with fine tip, that is surely possible. I had been soldering 144 pin fine-pitch controllers (0.64mm pin distance) with such equipment. And others (often women) did/do this on a daily basis.

    I cheaper "hobby" iron (I have such one) is distinctively less appropriate (you get what you pay for).

    And most important, it depends on one's skills. It is easy to ruin a PCB in less than a minute. In this regard, the O.P. does not seem too convinced of his soldering skills ...

  • 0
    Guru 13040 points

    Bob,

    I also second cb1 here.

    You are looking for a solution to what is not your actual problem. There are alternative components that suit your initial purpose, you might even find dinossaur DIP IC's. Though IMHO, SOIC's are the nicest size for non-professional smd do-it-youself folks.

    On the other hand, if the IC you are talking about has a good level of support, manufacturer might have development boards available, with the main part, the necessary discretes around it, and with .1" pitch access holes along the edges... that's normal on this market.

    Later on when you are happy with your DAC chip results and your product is a prototype success, then it is time to put some more money, make a batch of boards, a stencil, and take them to a professional company to solder your release candidate #1 batch. Might still be hand soldered at this stage, but professionally done.

    (And whatever excellent job you do on your first layout design, it WILL NOT be the one on your final product, trust me!)

    Happy developing

    Bruno

  • 0 in reply to f. m.
    Guru 27665 points
    I've done it (QFP64/0.5mm only though) with something more like a hobby iron but it isn't a simple one pass and you're done process for me and my hands aren't as steady as they use to be either.

    I'd agree though that if the OP isn't already comfortable with DIP and maybe even the wider spaced SOICs this may not be the best place to start. More doable if there is a mentor that can show you how to do it. This IC would be a good start before trying larger fine pitched devices though.

    The key is lots of flux and a good solder mask. On your first tries there is a good chance you'll burn the traces.

    Robert
  • 0 in reply to f. m.
    Intellectual 360 points

    I can't thank you guys enough for all of your very helpful and prompt feedback!  I do hope to one day work up to actually making prototype type projects with small IC's like this, so Amit, thank you for the info on how to solder it to the board - it should be helpful in the future - but for now it sounds like I will be purchasing the "DIP" version of the chip.  Just a few replies to comments from this thread:

    cb1 said:

    How did you wind up w/that SO small device? 
    MAX548ACPA (electrically identical) is available & stocked in an IMMENSELY EASIER TO HANDLE/SOLDER "8 pin DIP" (standard) package.

    I didn't even know the difference between "DIP" and other types of packaging :)  Now I do, so thank you for that.  Looks like I'll be ordering one of these chips momentarily.

    f. m. said:

    cheaper "hobby" iron (I have such one) is distinctively less appropriate (you get what you pay for).

    Yes, I had a hunch that my $10 soldering iron I've used in the past for things like soldering wires to a car stereo harness is not the tool to be using for something like this.  Now I know I will be purchasing a newer/better soldering iron before attempting something like this.


    f. m. said:

    And most important, it depends on one's skills. It is easy to ruin a PCB in less than a minute. In this regard, the O.P. does not seem too convinced of his soldering skills ...

    Correct.  I'll need to practice more before I attempt something like this.  For larger components I can get the job done but my soldering joints aren't exactly pretty.  I think I should be able to get better with more practice.

    Thanks again everyone!  Awesome forum.  Very helpful.

  • 0 in reply to Robert Adsett
    Guru 47900 points

    Robert Adsett said:
    my hands aren't as steady as they use to be either.

    Aren't as steady?   We're told, "Richter had to expand his scale" to (maybe) accommodate R.A.'s solid/stable grasp...

    (Truth in Advertising:  Friend Robert is not alone in such "condition."   This reporter often generates (unplanned/unwanted) "multiple key strikes" - (always) duly noted by crack (otherwise inattentive) staff...)     cb1  OOOut...

  • 0 in reply to cb1
    Guru 27665 points
    I have had a few comments from the better half about unexpected movements but no requests to reinforce building structures as of yet.

    Robert
  • 0 in reply to Robert Adsett
    Guru 47900 points

    Robert Adsett said:
    no requests to reinforce building structures as of yet.

    Good that - although I'd think (twice) about adding that planned, "second level."

  • 0 in reply to Bob Jennings
    Guru 13040 points
    By the way, bringing matters to this manufacturer, why don't you try DAC102S085CIMM? For similar amount of money that you were looking at, it gives you two more bits of resolution (not that great if you were thinking of some sort of automatic byte transfer via DMA, but then there's also DAC082x)
    It's SSOP, which is not too tiny but not too easy on your hands as SOIC. You can buy cheap breadboard adapters on Futurlec, such as 8PINSSOP.
  • 0 in reply to Bruno Saraiva
    Intellectual 360 points

    Bruno Saraiva said:
    By the way, bringing matters to this manufacturer, why don't you try DAC102S085CIMM? For similar amount of money that you were looking at, it gives you two more bits of resolution (not that great if you were thinking of some sort of automatic byte transfer via DMA, but then there's also DAC082x)
    It's SSOP, which is not too tiny but not too easy on your hands as SOIC. You can buy cheap breadboard adapters on Futurlec, such as 8PINSSOP.

    Thanks for the info, Bruno.  Actually, I chose the MAX549 because I found some example code that works with it.  This is the first time I'm interfacing with a DAC and wanted to use something that someone else had already had success with.  I know that might sound like I'm playing it very safe but I'm new to working with chips :)  ...Might try your suggestion next though.  Thanks!