Andy:
There was a techniques described a couple of years ago for using these chips
dead bug style. Mount the chip upside down on a piece of unetched PCB.
Bend the grounding pins down and solder directly to the groundplane.
I've just built a PIC controlled DDS using the AD9832 using a similar
technique. I stuck the chip to a small piece of copper mounted along the
middle and between the pins of an 18 pin DIL header and used very thin ecw to
extend the legs to the header pins. I bent the chips' legs very slightly to
allow easier access to them with the soldering iron.
Now here are some top tips!
When I got to the 14th leg, the wretched thing fell off so try only to bend the
legs once!
I managed to attach a wire to the stub of the leg by cutting a very sharp point
onto a length of 22swg tinned copper wire, wrapping the wire around the
soldering iron bit, tinning the end as soon as it was hot enough and then
prodding the tinned end of a piece of ecw against the stub using the home made
soldering bit. I found it best not to swear too loudly whilst doing this - a
steady hand is needed.
I potted the whole (very), ugly construction in epoxy resin and it's worked
well ever since!
I used a watchmakers eyeglass (my Dad's an horologist), for the really tricky
bits and although it didn't affect me too badly cross-eyed-wise, I suspect
Andy's comments should be noted.
Regarding a board for various DDS chips, I have a friend who owns a PCB milling
machine which will accept gerber files and will, apparently, cope with SMT
devices. He might be willing to run off a couple of boards if anyone would
care to design one? I haven't asked him by the way so he might not!
73 Martin
G4FKK
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