I moved from prototyping trough hole projects to SMD projects as most of the chips are surface mount now.
I have looked to get some kind of prototype board for SMD but only found SMD to DIP adapters which are bringing every pin to a dip and if there is a QFP package then usually are two rows thus making it impossible to use directly in a regular breadboard. Also it seems there is no place for placing anything on those boards.
After getting some of those and trying them out I decided to design my own PCB SMD PROTOTYPE BOARDS keeping in mind the following features:
- Being able to place some SMD components on the same board. (Decoupling capacitors are required to be as close to the chip as possible)
- Being able to remap the pins on the output connectors as needed.
- Use as small space as possible.
- Pads pre-connected with small traces that can be cut to accommodate for different schematics.
- Able to use them as is on the projects.
- Also given some proto space on the board not all the pins need to be exposed outside thus the number of the DIP pins do not need to match the IC pin number.
I came out with few boards so far:
I) TSSOP28 to DIP
A very small SMD board with only 20 pins directly exposed on the sides and breadboard friendly.
It has few pads and some vias wired to the Chip already.
As this is a prototype board wires can be soldered directly into the vias and brought where needed either to the edge or another pad.
Very thin traces connect some of the pads which can be cut as needed to fit the required schematic.
II) QFP 64, 48,32 to DIP
A medium size board that accepts three types of ICs QFP 64, 48,32 with a 0.8mm pin distance to DIP
This was made with Arduino, ARM, and small FPGAs projects in mind.
Fits within the original feature requirements, having prototype space, remapping of pins to the edge and thin traces can be cut to fit the schematic.
QFP144 is a prototype board that support ICs with 32, 48, 64, 80, 100, 144 pins with 0.5mm pin spacing.
On the internet could only find adapters that will transfer all pins out and no place to put any other components like small decoupling capacitors or anything for that matter.
This was designed for either big processors or big FPGAs.
No circuit requires all pins to be surfaced however with this board there are plenty of opportunities:
There are two DIP lines with 25 pins each that will accept regular headers.
On the other sides is possible to solder up to 2x20 pin headers thus allowing for another 80 pins to be surfaced
This allows for surfacing 130 pins out of the maximum 144 pins when using the biggest chip
All the pins are wired in such a way that allows for mounting decoupling capacitors on the bottom side for every pin. Also a 0 ohm resistor can be wired to the ground which is the inside square on the bottom.
Currently none of the pins are wired which allows for remapping of the pins as the user sees fit.
As this is a prototype board, all the vias are design with soldering in mind and 30 gauge (wrapping wire) can be soldered to them providing an easy way to bring the pins to the border.
The center zone on the bottom of the board allows for a 15x15 surface mount prototype soldering surface. As this is on the bottom the board will look neat from above when mounted. :)
The ground traces on the bottom side are plated allowing for increasing the surface using solder if they are used as ground and also at the same time they are thin enough to allow for cutting them in order to use more prototype surface.
There are 4 holes for mounting the board 55mm apart.
There are guiding lines on the top to allow for easy detection of the lines when smaller ICs are used.
This board can be used as the main board of the project as is big enough to accommodate lots of parts. The edge pins can be used to connect to other prototype boards as needed, either trough hole or SMD and they can act a daughter boards or shields.
I am looking for others to be able to use these boards and improve on them.
The kits would contain the PCB board(s) and pins and maybe some of the most used components like few SMD resistors and capacitors of common sizes.
We could also recommend ICs that fit on the board that can be add-on.