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Prop Dip40 QFN — Parallax Forums

Prop Dip40 QFN

DigitalBobDigitalBob Posts: 1,513
in Propeller 1
I just wanted to post a picture my prop dip 40 QFN. With the recent "0" stock and 3 month lead time of the dip 40 I figured I needed a plan "B". Your comments welcome.
Prop Dip 40 QFN.jpg
1024 x 768 - 314K

Comments

  • JRetSapDoogJRetSapDoog Posts: 954
    edited 2015-08-08 04:18
    Looks a lot like (and functions the same as) a lead-frame (but where are the bonding wires, lol). Did you decouple all four power-ground pairs onboard (don't see any caps offhand, but perhaps they're underneath). Or maybe you plan to do caps off the board (since its pin compatible and all), but I was guessing that offboard could be a bit too far away from the chip. Anyway, looks like your Plan B is ready to go if called upon. For a plan C, I'll sell you my remaining D40's at "only" 24.95 a piece. Just kidding! Talk about price gouging! Besides, I need them. Next, you're ready to add an eeprom and a v-reg. onboard (though not for drop-in replacements, of course). Cheers!
  • Alexander (Sandy) HapgoodAlexander (Sandy) Hapgood Posts: 360
    Looks like a pretty solid plan B. How did you solder the prop onto the board? Doesn't look like you would be able to use a soldering iron?
  • DigitalBobDigitalBob Posts: 1,513
    I did not add any caps just a pin to pin match up. Soldering for these QFN 's is a little tedious I used solder paste ( nothing more than ground up solder powder mixed when flux) and a hot air reflow.
  • WBA ConsultingWBA Consulting Posts: 2,934
    Looks good. It appears that you oversized the pads to help with soldering? Here's a link to my QFN module that is also in Propeller DIP40 pinout format:
    http://forums.parallax.com/discussion/131867/
    Can be used with just the QFN, or fully loaded as a complete Prop circuit. It also works with a DIP40 as shown in this post:
    http://forums.parallax.com/discussion/comment/1027197/#Comment_1027197
  • DigitalBobDigitalBob Posts: 1,513
    Nice I like your boards WBA. Have thought about SMT ram instead of dip
  • WBA ConsultingWBA Consulting Posts: 2,934
    Actually, yes. Version 2 of my module that is about 80% done as far as layout has an SMT package for the EEPROM, but also squeezes in the QFP prop instead of the QFN. It also has a uSD socket and 3.3v regulator. That means a full propeller circuit with uSD the size of a DIP40 and can run off of 4.5~12 volts. Adding the uSD socket also means that no prop plug is needed because I will be loading an SD bootloader into the 64k EEPROM when they ship. It will also work with a DIP40 as a sort of "underpack" (as opposed to backpack).
  • DigitalBobDigitalBob Posts: 1,513
    Looks like the Prop dip40 supply is getting pretty low over at parallax. I don't know if anymore are out there at mouser , digikey etc.
  • PaulPaul Posts: 263
    From Findchips.com...

    Jameco has 1300+ at $12/$13 a pop.
  • DigitalBobDigitalBob Posts: 1,513
    I checked Jameco and it said only 51 can ship today and the balance in October.
  • DigitalBobDigitalBob Posts: 1,513
    Qfn
  • Heater.Heater. Posts: 21,230
    Looks good. I seriously hope DIP Props are not going away.

    Many times when people make a breakout board like that the put the chip at a 45 degree angle so as to make routing nicer.
  • WBA ConsultingWBA Consulting Posts: 2,934
    Heater. wrote: »
    Many times when people make a breakout board like that the put the chip at a 45 degree angle so as to make routing nicer.

    True, but the way the Propeller's die was routed in the QFN, a square position lends the greatest routing ease. Here is a view of my top trace routing on my M44D40+ module:

    M44D40+_top_trace_routing.jpg
    715 x 268 - 83K
  • Heater.Heater. Posts: 21,230
    Looks like it fits nicely. No worries.
  • MicksterMickster Posts: 2,693
    https://www.antratek.com/propeller-chip
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