After struggling to make a neat job of effectively decoupling the power pins on my PIC18F I decided something needed to be done!
This instructable shows what I did.....
This is my first instructable (I thought it was time to give something back!) so go easy on the comments ;-)
The first picture (below) shows the completed board - looks neat (apart from the burnt flux!) doesn't it....read on!
Step 1: Lets Begin...
I find that the best way to solder these fine (ish) pitch devices is to use plenty of good flux and some leaded solder (dont tell the environment though ;-) !).
Step 2: Copper Tape and Capacitor Lead Forming.
Next you need to poke the capacitor legs through the adaptor board with one capacitor leg placed through the positive supply (to be decoupled) hole and the other leg placed through the ground pin connection. This is fairly easy with the PIC18F since the power and ground connections are usually close together.
Next you need to solder small pieces of solid core wire onto the ground legs of each cap as shown in the images below. These pieces of wire then need to be formed such that they overlap the copper tape in the centre. This copper tape will become our makeshift ground plane.
Step 3: Soldering the Decoupling Capacitors.
The image below shows the soldered connections.
Step 4: Insulating the Negative Plane.
First you need to insulate the existing copper tape 'ground plane' with some tape. I used Sellotape but i am sure there is something more suitable! Maybe Kapton tape?
Make sure that the ground is well insulated and then move on.
Next you need to stick another similar sized piece of copper tape over the insulated ground plane.
The image below shows the ground plane insulated with Sellotape.
Step 5: Add the Positive Plane.
Make sure you get the copper tape well stuck down!
Step 6: More Capacitor Lead Forming!
See images below for an idea of how it should look!
Step 7: A Bit More Soldering.
Again, make sure you make a neat job of the soldering and don't use too much solder.
If you look close you can see the Sellotape just poking out from the edges of the copper tape.
See image below :-)
Step 8: Connecting the Supply Wires.
See image below for details.
Step 9: Making Sure You Haven't Shorted the Whole Thing Out :-)
The DMM (set to Ohms measurement) should show open circuit between the red and black wires if all is connected correctly.
See image below showing what a working board should show on the DMM.
Once it works you have a nice, reusable board suitable for prototyping and showing off to people without heaps of wires etc.
The finished article 'should' provide decent decoupling of the supply pins and will show some of the benefits of using a ground and power plane although the capacitance between the two copper 'plates' is likely to only be a few nF (nano-Farads) at best.
If you liked this instructable and have an interest in electronics please pop over to PCBPolice and say hello :-)