Shop OBEX P1 Docs P2 Docs Learn Events
QFN Chips — Parallax Forums

QFN Chips

GarthGarth Posts: 18
edited 2008-03-27 12:49 in Propeller 1
I am interested in working with the QFN format of the propeller chip. My question is it looks like it's a socketed chip, what socket is used for thru hole mounting?

Thanks
Garth

Comments

  • QuattroRS4QuattroRS4 Posts: 916
    edited 2008-03-27 02:35
    No they are leadless SMD devices .. see attached pdf .. as a guide..

    Regards,

    ········· John



    ▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
    'Necessity is the mother of invention'

    Post Edited (QuattroRS4) : 3/27/2008 2:42:26 AM GMT
    pdf
    pdf
    qfn.pdf
    877K
    qfn.pdf 876.6K
  • mynet43mynet43 Posts: 644
    edited 2008-03-27 03:22
    If you want to work with the QFN chips, you'll have to learn how to solder them.

    I've finally figured out how to do it, although it's still not easy.

    Attached is a pic of a little board with four different QFN chips on it.

    Let me know if you need more info.

    Jim
    QFN Board.jpg
    3264 x 2448 - 2M
  • GarthGarth Posts: 18
    edited 2008-03-27 03:31
    Thanks guys. That will help.
  • Paul BakerPaul Baker Posts: 6,351
    edited 2008-03-27 06:25
    The QFN package is intended for reflow production lines. The reason this is the case is there is an exposed metal plate underneath the chip, this plate is intended to be soldered to a grounded pad on the board. but is inaccessible to a hand iron. Hot air pencil and solder paste works, using vias as a port to the back of a chip works ok but isn't ideal (This is where you put fairly large vias in the pad (I put one in each quadrant and one in the center), this connects the pad to the back ground plane and you dump as much solder into the vias as it can take, this solder slug will flow through the via and make contact with the chip's plate).

    ▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
    Paul Baker
    Propeller Applications Engineer

    Parallax, Inc.
  • LeonLeon Posts: 7,620
    edited 2008-03-27 12:40
    For QFN manual assembly at home I do something similar - I put a largish via in the pad, drag-solder the leads, and feed solder in to the via with a soldering iron tip.

    Leon

    ▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
    Amateur radio callsign: G1HSM
    Suzuki SV1000S motorcycle
  • LoopyBytelooseLoopyByteloose Posts: 12,537
    edited 2008-03-27 12:49
    Great tip Paul and Leon.
    I hadn't realized tht a 'largish via' connected to ground would make it so easy.

    ▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
    PLEASE CONSIDER the following:

    Do you want a quickly operational black box solution or the knowledge included therein?······
    ···················· Tropically,····· G. Herzog [noparse][[/noparse]·黃鶴 ]·in Taiwan

    Post Edited (Kramer) : 3/27/2008 12:56:12 PM GMT
Sign In or Register to comment.