Are you aware of any possibility to buy online a PCB ready made
for the AD9854 ? It would suffice a layout that brings all the pins
to more manageable pads where to connect the rest of the circuit.
I checked the Analog Devices site, but they have (for an outrageous
price...) only an evaluation board for the 9854, complete with the chip.
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. Then
get some 0805 chip capacitors and solder one end of these, standing upright,
to the groundplane as close to the power supply pins as possible. Then
using thin wire - eg a single strand of multistranded wire - connect the
appropriate pins direct to the caps; then the signal pins to the rest of the
circuit. This can give an RF layout every bit as good as a proper double
sided PCB. It looks messy, but so what, it works !
In my last job I did a bit of chip and bond microwave circuitry. Now
that
really IS small ! Bonding 25 micron gold wire onto 0.1mm pads on bare
GaAsFET chips.
I hope you didn't do that with unaided hands... otherwise I will dub
you SuperMan..:-)
No, sorry, we had a lab wirebonder. It always needed cleaning before use
as there was inevitably some individual that had left it in a dirty state
with the covers off.
Andy
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