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Propeller QFN Land Pattern HERE!!! — Parallax Forums

Propeller QFN Land Pattern HERE!!!

cgraceycgracey Posts: 14,206
edited 2006-12-12 08:54 in Propeller 1
Here is the land pattern for the QFN package. The LQFP will be ready, too, shortly.

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Chip Gracey
Parallax, Inc.

Post Edited (Chip Gracey (Parallax)) : 7/27/2006 1:13:28 AM GMT
pdf
pdf
P8X32A-M44 Land Pattern.pdf
63K
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Comments

  • NewzedNewzed Posts: 2,503
    edited 2006-07-26 22:59
    Chip, are there any plans to make the Propeller available in an SOIC package?

    Sid
  • cgraceycgracey Posts: 14,206
    edited 2006-07-27 01:10
    No, but it might be possible. I'll check into it.
    Newzed said...

    Chip, are there any plans to make the Propeller available in an SOIC package?

    Sid

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    Chip Gracey
    Parallax, Inc.
  • cgraceycgracey Posts: 14,206
    edited 2006-07-27 01:11
    Here's the LQFP land pattern....

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    Chip Gracey
    Parallax, Inc.
    pdf
    pdf
    P8X32A-Q44 Land Pattern.pdf
    35K
  • NewzedNewzed Posts: 2,503
    edited 2006-07-27 11:42
    That would be excellent, Chip.· The SOIC I can handle - I wouldn't even try to solder the other two packages.

    Sid
  • parskoparsko Posts: 501
    edited 2006-07-27 12:08
    Wow, I have a hard enough time soldering 0.1" spacing!

    I too, would be interested in the SOIC package. How much smaller would a SOIC be from the DIP (if it were materialized)?

    -Parsko
  • NewzedNewzed Posts: 2,503
    edited 2006-07-27 12:16
    Parsko, it would be half as long since the pins would be on .050 centers.· Width would probably be about·.375.

    Sid
  • Kaos KiddKaos Kidd Posts: 614
    edited 2006-07-27 12:39
    Ok, what does " 44X 0.4 X 1.8mm" mean?
    the .4 is the width, 1.8 is the length, but the 44? Is that the pin count?

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    Propeller + Hardware - extra bits for the bit bucket =· 1 Coffeeless KaosKidd

    ·
  • NewzedNewzed Posts: 2,503
    edited 2006-07-27 12:45
    Yes - 44 is the pin count.· Pin size of .4 x 1.8 translates to .0157 x .071.· Pin spacing is .0314.

    Sid
  • Direct Digital LabsDirect Digital Labs Posts: 27
    edited 2006-07-27 15:46
    Thanks Chip!

    -Dan
  • Kaos KiddKaos Kidd Posts: 614
    edited 2006-07-27 17:45
    Grrr... It's so hard to make these things in expresspc... it really is...
    I need a REAL layout program...
    THanks Chip for posting the specs...

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    Propeller + Hardware - extra bits for the bit bucket =· 1 Coffeeless KaosKidd

    ·
  • cgraceycgracey Posts: 14,206
    edited 2006-07-27 19:32
    Sid,

    I looked into this and I cannot find a packaging supplier who does 40- or 44-pin SOIC. I think this is no longer done. All I can find are expensive ZIF sockets.

    Anyway, the LQFP is intended to be the surface-mount version of the Propeller which can be hand-soldered easily. You just have to get some flux on the legs and drag your iron across them. If you've never done this, you'd be amazed at how well it works. We use water soluble flux here, so it rinses right off.

    To solder a QFN part by hand, you need to get some solder bumps on its pads using a hot-air pencil, apply some extra flux, position the part and heat up the board and QFN with hot air. The LQFP is much easier to deal with by hand. In production, when using a solder stencil, paste, a pick-and-place, and reflow oven, it's all the same. The QFN is just cuter. It takes one-half the area of the LQFP because it's only 9x9mm and doesn't have any legs sticking out. We would have used the QFN on the demo board, but then people wouldn't be able to probe the pins.
    Newzed said...

    Chip, are there any plans to make the Propeller available in an SOIC package?

    Sid

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    Chip Gracey
    Parallax, Inc.
  • NewzedNewzed Posts: 2,503
    edited 2006-07-27 20:03
    Chip, are you saying that with, say an Expresspcb board, there is enough residual solder on the board and on the LQFP, to make a secure bond with just flux and a hot iron?· Do you have any defective chips chips I could practice with?· I would have to make an Express footprint, which would be a pain but I could do it.

    Sid
  • cgraceycgracey Posts: 14,206
    edited 2006-07-27 20:32
    Well, you would need a little bit of solder on the iron to supply the joints. If you email me on this forum, I will put a few bad chips in a bag and send them to you for practice.
    Newzed said...

    Chip, are you saying that with, say an Expresspcb board, there is enough residual solder on the board and on the LQFP, to make a secure bond with just flux and a hot iron?· Do you have any defective chips chips I could practice with?· I would have to make an Express footprint, which would be a pain but I could do it.

    Sid

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    Chip Gracey
    Parallax, Inc.
  • Paul BakerPaul Baker Posts: 6,351
    edited 2006-07-28 04:06
    Here's a video clip showing the method described by Chip, while the demo is on an SOIC package, it works for LQFP as well.

    http://www.howardelectronics.com/xytronic/Images/Drag%20Soldering%20107.wmv


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    ...

    Post Edited (Paul Baker) : 7/28/2006 4:43:25 AM GMT
  • Kaos KiddKaos Kidd Posts: 614
    edited 2006-07-28 14:50
    That was hot air used to melt the flux first?
    If so, I might be able to do this...
    Sid, do you know if you can share lib's with expresspc? If so, I'd love a copy of that foot print...

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    Propeller + Hardware - extra bits for the bit bucket =· 1 Coffeeless KaosKidd

    ·
  • NewzedNewzed Posts: 2,503
    edited 2006-07-28 15:24
    KK, here is a footprint of the LQFP for Expresspcb.· I think it is correct, but as always, it needs to be checked.· Copy the file into:

    Express540\PCBComponents_Custom

    Sid
    p
    p
    Prop LQFP.p
    1K
  • NewzedNewzed Posts: 2,503
    edited 2006-07-28 16:04
    I just ran a test etch pattern on SuperMill·for the LQFP I posted above.· According to the footprint, the distance between the left-hand pad and the right-hand pad on any side should be .315.· I measured about .317 by visually aligning my calipers in the center of the two pads.· I think that is pretty good!· Chip is sending me some chips so I'll have to wait for them to really check it out.

    Sid
  • Kaos KiddKaos Kidd Posts: 614
    edited 2006-07-28 16:09
    Way cool!
    Thanks... I'll check it out when I get home... (Aug 13...)

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    Propeller + Hardware - extra bits for the bit bucket =· 1 Coffeeless KaosKidd

    ·
  • NewzedNewzed Posts: 2,503
    edited 2006-07-28 16:40
    Forgot to mention - I switched to my .015 router for the above etch test.· Held my breath for fear it would snap off, but it didn't.

    Sid
  • NewzedNewzed Posts: 2,503
    edited 2006-07-28 16:54
    Chip, on the LQFP, where is Pin 1?

    Thanks

    Sid
  • Paul BakerPaul Baker Posts: 6,351
    edited 2006-07-28 17:05
    There is typically a dot or notch at one corner, orienting the chip so the mark is in the upper left, Pin 1 is to the left of the mark, and the numbers progress counter-clockwize
    ·

    attachment.php?attachmentid=42651

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    lqfp.GIF
    266 x 191 - 2K
  • NewzedNewzed Posts: 2,503
    edited 2006-07-28 17:14
    That's true for a DIP, Paul.· I don't think the LQFP works that way.· Pin 1·is probably the 4th pin from the left in the top row but I'M not sure.

    Sid
  • Phil Pilgrim (PhiPi)Phil Pilgrim (PhiPi) Posts: 23,514
    edited 2006-07-28 17:26
    The pinout is given on page 14 of the Propeller manual. You're both right -- in a way. Pin 1 corresponds to the dot, but it's not P0. P0 is the fourth pin from the left in the top row (pin 41).

    -Phil
  • NewzedNewzed Posts: 2,503
    edited 2006-07-28 19:14
    On the LQFP, are all the Vdd's and Vss's connected together internally?

    Sid
  • Phil Pilgrim (PhiPi)Phil Pilgrim (PhiPi) Posts: 23,514
    edited 2006-07-28 19:28
    Sid,

    Even if they are, it's a good practice to connect them all on the PCB, too. At least one pair should be bypassed near the chip, as was done on the Demo Board. But it certainly wouldn't hurt to put bypass caps on all four sides if you've got the room.

    -Phil
  • Paul BakerPaul Baker Posts: 6,351
    edited 2006-07-28 19:40
    Sorry Sid, ussually when someone asks where pin 1 is, they mean the package's first pin, not bit 0 of an I/O port. A simple misunderstanding.

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  • NewzedNewzed Posts: 2,503
    edited 2006-07-28 19:46
    Phil, I'm trying to see if I can layout a Propeller board for SuperMill.· Space is at a premium - I can only go 1.7 top to bottom - plus it is single sided.· Even with jumpers I think it is impossible but I thought I would give it a try.· Need a keyboard and a VGA.· I have some USB female B connectors for PC mount which I cn use for programming.· I've already run a test etch so I can do the LQFP layout.· So I need to know if all the Vdd and Vss pins are tied together internally.· Bypass caps I can probably handle.

    Sid
  • NewzedNewzed Posts: 2,503
    edited 2006-07-28 19:50
    My error, Paul.· The question was not properly stated.

    Sid
  • SeekerSeeker Posts: 58
    edited 2006-07-28 22:58
    Kaos Kidd said...
    Grrr... It's so hard to make these things in expresspc... it really is...
    I need a REAL layout program...
    THanks Chip for posting the specs...

    Try Eagle.· It's easy to use, and·works great. Plus there is a freeware version that is only limited by max board size.

    http://www.cadsoftusa.com/

    And no, I don't work for them.· [noparse]:)[/noparse]
  • cgraceycgracey Posts: 14,206
    edited 2006-07-29 00:04
    Yes. On the die, the VSS's are internally connected and so are the VDD's. It doesn't hurt to connect them externally, especially when the I/O pins are driving lots of current.
    Newzed said...

    On the LQFP, are all the Vdd's and Vss's connected together internally?

    Sid

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    Chip Gracey
    Parallax, Inc.
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