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Propeller 44-pin QFN? — Parallax Forums

Propeller 44-pin QFN?

VaatiVaati Posts: 712
edited 2009-05-08 02:34 in Propeller 1
How in the world would you connect the QFN chips to anything?· Would you have to use a custom PCB or some wire-wrap board?· I just can't picture in my mind's eye how you would hook one of those up...· Unless there is some special proto board that has an area designed for that specific chip...· ?idea.gif

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Comments

  • mctriviamctrivia Posts: 3,772
    edited 2009-05-01 23:34
    you need a pcb or if you are crazy solder to the chip upside down but I do not recommend that. my propmod pcb are only $5 and they use the qfn chip if you want to try.

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    Need to make your prop design easier or secure? Get a PropMod has crystal, eeprom, and programing header in a 40 pin dip 0.7" pitch module with uSD reader, and RTC options.
  • VaatiVaati Posts: 712
    edited 2009-05-01 23:37
    So... Which one is $5? I can't seem to find it...

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    86208998628034825342117067982148086513282306647093844609550582231725359.....
  • mctriviamctrivia Posts: 3,772
    edited 2009-05-01 23:42
    http://forums.parallax.com/forums/default.aspx?f=15&m=341159

    both the 1x1 and full size are $5 for the pcb.

    ▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
    Need to make your prop design easier or secure? Get a PropMod has crystal, eeprom, and programing header in a 40 pin dip 0.7" pitch module with uSD reader, and RTC options.
  • Timothy D. SwieterTimothy D. Swieter Posts: 1,613
    edited 2009-05-02 02:25
    The QFN can be hand soldered if you are skilled and have the a little time on your hands. Also designing a PCB with a little longer tracks helps too as well as a via or two through the center of the board to the ground plane of the chip. Of course, you could also use a hot air pencil or a home made SMT oven to get the job done too.

    Personally I hope to do the dead bug soldering some day on this IC because I think it would be fun to see what it looks like and to say I have done it.

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    Timothy D. Swieter, E.I.
    www.brilldea.com - Prop Blade, LED Painter, RGB LEDs, 3.0" LCD Composite video display, eProto for SunSPOT
    www.tdswieter.com
  • RaymanRayman Posts: 14,827
    edited 2009-05-02 02:31
    I would avoid QFN, unless you are a professional! The QFP can be hand soldered, and it's just a little bit bigger.

    (What I really mean is that I've tried using QFN chips and it's no fun!· If the lead spacing is big enough, it isn't so bad, but I wouldn't dare try using the Prop QFN without automated machinery.)

    [noparse][[/noparse]Ok, it take that back.· The Prop QFN lead spacing is just enough that I might try it if I were desperate for space.]

    Post Edited (Rayman) : 5/2/2009 2:54:11 AM GMT
  • mctriviamctrivia Posts: 3,772
    edited 2009-05-02 03:38
    I recommend a toaster oven. have not done prop qfn yet but have done bga

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    Need to make your prop design easier or secure? Get a PropMod has crystal, eeprom, and programing header in a 40 pin dip 0.7" pitch module with uSD reader, and RTC options.
  • LeonLeon Posts: 7,620
    edited 2009-05-02 03:59
    I've hand-soldered QFNs without too many problems, using drag-soldering with plenty of gel flux. The pads need to be extended slightly.

    Leon

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    Amateur radio callsign: G1HSM
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  • PhilldapillPhilldapill Posts: 1,283
    edited 2009-05-02 05:59
    I've soldered a few Accelerometer chips that were 20pin QFN. My trick was putting a dap of solder paste on the pads of the chip, then laying that on my home-made PCB. It stays in place due to the solder paste. Then, I get the PCB with the chip on it, and put it on an upside-down clothes iron, on full heat. If your iron is hot enough, the paste will melt and the chip will self solder. Pretty cool technique if I do say so. [noparse]:)[/noparse]

    Word to the wise - don't try ironing clothes with it afterwards!
  • LeonLeon Posts: 7,620
    edited 2009-05-02 09:24
    That's an interesting technique. It's similar to the electric skillet that some people use, with the advantage that the heat is applied from the top. It doesn't work with other packages and discretes, presumably.

    A (somewhat loony) acquaintance of mine bought some normally very expensive Xilinx Virtex BGA FPGAs cheap on Ebay, because they had been removed from PCBs, and experimented with them by gluing them upside down to a prototyping board and soldering wire-wrap wire to what remained of the balls. The same technique can be used with QFNs, of course, as Timothy has suggested.

    Leon

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    Suzuki SV1000S motorcycle

    Post Edited (Leon) : 5/2/2009 9:32:39 AM GMT
  • Toby SeckshundToby Seckshund Posts: 2,027
    edited 2009-05-02 11:16
    As I have often said the thought of getting chips up to dull red realy worries me, even though everything I am writting this on has suffered exactly that. I like the idea of an upside-down clothes iron as that is what I use to toner tranfer my PCBs.
  • mctriviamctrivia Posts: 3,772
    edited 2009-05-02 12:47
    problem with clothes iron is you are touching the ic and thus could move it. If you buy(or already have) a toaster oven with infared or quartz elements you can do several boards at once and when you are hungry make some lunch. Just don't do at the same time. You can pick them up pretty cheap. I paid $50 Canadian Tire money for mine(same value as Canadian money).

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    Need to make your prop design easier or secure? Get a PropMod has crystal, eeprom, and programing header in a 40 pin dip 0.7" pitch module with uSD reader, and RTC options.
  • LeonLeon Posts: 7,620
    edited 2009-05-02 13:00
    It should be OK if the iron is lifted vertically. Any misalignment will be corrected by the surface tension of the molten solder pulling the chips into place.

    Leon

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    Amateur radio callsign: G1HSM
    Suzuki SV1000S motorcycle
  • kwinnkwinn Posts: 8,697
    edited 2009-05-02 14:55
    It sounded to me like Phildapill did not touch the iron to the chip. He said " I get the PCB with the chip on it, and put it on an upside-down clothes iron " which sounds like he sat the board on the iron with the chip on the top of the board.

    Phildapill, is that correct?
  • LeonLeon Posts: 7,620
    edited 2009-05-02 15:06
    I misread his post, that is what he did. It's essentially the same as the skillet technique.

    Leon

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    Amateur radio callsign: G1HSM
    Suzuki SV1000S motorcycle
  • VaatiVaati Posts: 712
    edited 2009-05-02 19:18
    Okay, well I have heard that it is indeed possible to make a "wave soldering machine" out of a toaster oven and some other stuff. Has anyone on these forums done that/able to confirm that it's possible?

    Thanks.

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    86208998628034825342117067982148086513282306647093844609550582231725359.....
  • PhilldapillPhilldapill Posts: 1,283
    edited 2009-05-02 19:22
    Vaati, I think you may be thinking of a different type of machine called a "reflow" oven. A wave soldering machine is pretty complicated. It literally flows a "wave" of molten solder just barely under neath the board to solder through-hole components. The wave has to be very controlled so it doesn't splash onto the top of the board.

    A reflow oven is pretty easy to do. It basically just heats up the whole board at a controlled rate, causing the solder paste to "reflow", i.e. melt and bond chips to board. Timothy D. Swieter made a good Prop Controlled version, but I can't find the post ATM. Timothy?
  • mctriviamctrivia Posts: 3,772
    edited 2009-05-02 22:17
    i would like to rewire mine so it was automatic. write now I just manually adjust the temperature to set temperatures for set time frames. works pretty good but has to be baby sat for 10 min

    ▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
    Need to make your prop design easier or secure? Get a PropMod has crystal, eeprom, and programing header in a 40 pin dip 0.7" pitch module with uSD reader, and RTC options.
  • rjo_rjo_ Posts: 1,825
    edited 2009-05-03 05:57
    mctrivia,

    I think there is a need for a turnkey solution.... the stuff you guys take for granted would be news to people like me.
    I wouldn't know where to start. There have been volumes said about it... and they are all lost to posterity... and to me[noparse]:)[/noparse]
    What the world needs is a kit... so, when this question gets asked again.... the answer is... get mctrivia's kit[noparse]:)[/noparse]

    This where serious hobbyists need to go... and there isn't a good way to get there right now.

    Rich
  • SRLMSRLM Posts: 5,045
    edited 2009-05-03 06:49
    If you make a reflow oven controller, put it on Gadget gangster and advertise it in the sandbox. You'd certainly get some customers...
  • mctriviamctrivia Posts: 3,772
    edited 2009-05-03 20:31
    i was thinking about the reflow idea and really all that is needed is a temperature sensing ic, relay, and a prop. all parts i already have. I will design one based on my propmod and order a gangster boss board to make the kit on that.


    rjo_: I know you have asked for a kit for the propmod. I have made a kit that includes all parts and a few spares of the really small caps and resisters for $12 for the 1x1. You need to get your own prop or add $12 and I will include one.

    ▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
    Need to make your prop design easier or secure? Get a PropMod has crystal, eeprom, and programing header in a 40 pin dip 0.7" pitch module with uSD reader, and RTC options.
  • mctriviamctrivia Posts: 3,772
    edited 2009-05-03 21:09
    ok realised my temperature probe can't take 450C can't seem to find one that can either.

    ▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
    Need to make your prop design easier or secure? Get a PropMod has crystal, eeprom, and programing header in a 40 pin dip 0.7" pitch module with uSD reader, and RTC options.
  • SRLMSRLM Posts: 5,045
    edited 2009-05-03 22:05
    Don't forget some sort of display device...
  • mctriviamctrivia Posts: 3,772
    edited 2009-05-04 01:01
    ya a small led temp display or lcd would work for that. Even just a done bell would work for those on a budget.

    ▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
    Need to make your prop design easier or secure? Get a PropMod has crystal, eeprom, and programing header in a 40 pin dip 0.7" pitch module with uSD reader, and RTC options.
  • mctriviamctrivia Posts: 3,772
    edited 2009-05-04 01:14
    found a sutable temperature probe. PT100 just not a good place to buy it

    ▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
    Need to make your prop design easier or secure? Get a PropMod has crystal, eeprom, and programing header in a 40 pin dip 0.7" pitch module with uSD reader, and RTC options.
  • mynet43mynet43 Posts: 644
    edited 2009-05-04 01:52
    I use a skillet with an IR temperature sensor. It's handheld and has a little laser built in, so you can get the temp of one chip.

    See pic.

    Jim

    P.S. I discovered where the Swine Flu started.
    I thought you'd like to know.
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  • mctriviamctrivia Posts: 3,772
    edited 2009-05-04 02:14
    ya those work pretty well but would not let you hook to prop so easily. i have one i use for measuring trace temperatures on high current pcb.

    ▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
    Need to make your prop design easier or secure? Get a PropMod has crystal, eeprom, and programing header in a 40 pin dip 0.7" pitch module with uSD reader, and RTC options.
  • Timothy D. SwieterTimothy D. Swieter Posts: 1,613
    edited 2009-05-04 12:34
    450c? Why so high? The lead-free solder profile only goes up to 250c or 260c.

    My reflow toaster oven uses a Prop, the Parallax thermocouple kit, the LM9033a display from Brilldea and a couple buttons, leds and a piezo. It really isn't a kit, but eventually I can post more pictures. There is another thread on it around here. I didn't use relays to control the lights, fan or heating element but I used ac crossing detection and thyristors.

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    Timothy D. Swieter, E.I.
    www.brilldea.com - Prop Blade, LED Painter, RGB LEDs, 3.0" LCD Composite video display, eProto for SunSPOT
    www.tdswieter.com
  • YodaYoda Posts: 132
    edited 2009-05-07 18:31
    I have a question? I am interested in using the toaster oven approach for soldering smd devices. I am starting to see a lot of designs in this group that have devices on both sides of the pcb. How would one attach devices to both sides using this technique? Seems you can only do one side or am I missing something?

    Dave
  • James LongJames Long Posts: 1,181
    edited 2009-05-07 19:00
    Yoda said...
    I have a question? I am interested in using the toaster oven approach for soldering smd devices. I am starting to see a lot of designs in this group that have devices on both sides of the pcb. How would one attach devices to both sides using this technique? Seems you can only do one side or am I missing something?

    Dave

    Dave,

    Using a toaster oven, dual sided boards are possible. There are two things you must do to accomplish this. You must assemble them one side at a time, and you must hold the board up off the components on the second reflow.

    The solder may go liquid on the second run (bottom side), but the surface tension of the solder will hold your parts on.

    the skillet method only allows one side to be populated, if that was what you were asking.

    James L

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    James L
    Partner/Designer

    Lil Brother SMT Assembly Services
  • mctriviamctrivia Posts: 3,772
    edited 2009-05-07 23:00
    when making boards i only use the toaster oven for 1 side so I make sure any bga or qfn components are on one side. I hand solder all the components on the other side. But as James Long said it is possible to do both sides.

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    My new unsecure propmod both 1x1 and full size arriving soon.
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