If you don't know about the AD8307 from
Analog Devices then find out about it! This is my primary means of measuring
RF in my shack. The PCB is mounted on standoffs, with finger stock (in
shadow) providing good low inductance earth. Using SMT let me fit the circuit
into a small box, and leaves plenty of space for the feed thru caps. The
big black item in the top left is a Transzorb, a mixture of a reverse bias
diode and a zener.
PLL Prototype board for a LMX2306. SSOP
packages are quite small, and you cant easily birds nest them. Making a
PCB using on the iron on method is possible, but for the finer pitch work
like this I used the UV method (Kinston Pre-Sensitized Board and Developer).
I've made special PCB footprints up for the coaxial tails (far left). The
bottom of the PCB is a ground place, and the misc solder blobs you see
on the board are where the vias to the ground plane are. You can also see
in the bottom middle of the picture the solder side of a 10 Way 0.1" header.
It's much easier to mount thru hole parts on the ground plane solder, so
all your active connections stay on one side. Where you dont want ground,
just use a drill to clear plane near the through hole lead.
This is part of my VHF vco. I've used Coil
Craft surface mount spring inductors, although you could wind your own
and surface mount them yourself. It's amazing how many people forget that
with a bit of lead bending, you can turn leaded parts (like hand wound
coils) into SM parts.
Wondering what it is? It's a PI format
RF attenuator. Two SMA connectors are soldered back to back on some brass
shim (thin brass plate). The SMT resistors (1206) then get soldered in.
A brass shim is used for the lid (pulled back in this picture). All joints
are then soldered shut. Performance??? Flat to 3.5GHZ!
Fig 1 - 5 Minute PCB made with Dalo pen
and etched in acid. Quick and easy to make.
(Components not loaded)
Fig 2 - PnP Blue PCB - This is a 45MHz digital IF strip. A little bit more time is required to make the pcb overlay on a PCB cad package. Very easy to use SO-IC parts with this method. Note the use of leaded parts as (voltage regulator, DIP switch and Resistor Pack) and SMD parts together.
Fig 3 - Another application of SMD! Note the supply decoupling capacitor on the corner pins of the wire wrap socket.
Fig 4 - A professional PCB with SMD devices (from my Thesis work)
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Last Updated at 22:45 Hours on 13/8/01.