Nice idea Jared :-)
And great post Jim!
MotoFab wrote:Surface mounting TO220 package power transistors onto a board is a mechanically sound method for sure. For it to be successful, there are a couple of things to consider.
Another one is that a TO220 laying down uses a LOT of space. The DPAK stuff might be more appropriate and can be had with very low RDson and high current handling too.
Regarding the end-user-assembly, most users do not have a soldering iron with enough heat capacity to flow the backside of a TO220 part in a reasonable time. This doesn't mean a small iron turned up to a high temperature.
Good point!
About ideas for pcb design, I agree it's sort of premature. I don't really have any ideas because the circuit is still sort of blank sheet at this time.
I agree, premature, and yes, it more or less is blank at this stage, yes.
At least I think it is, or maybe I think it should be until other related decisions have been made.
Agreed :-) Though the time for PCB's is coming in the medium term so some decisions will have to be made in that same time frame.
I have some ideas about boards, but they can be summarized fairly quickly :
Not enough room on a single 160x100 eurocard for what we need.
Therefore two eurocards required to be sandwiched or similar.
Must accept the Tech Arts card in IDC socket form.
Tech Arts card should sit close to one end such that DB9 can be flush for users that can't afford to upgrade to USB
High V/I inputs should be separated AND isolated from low V/I inputs.
High V/I inputs should be separated AND isolated from low V/I outputs.
Inputs should be separated and isolated from outputs.
All of this is discussed in more detail (and more clearly) in the wishlist thread above.
Obviously this is for our first version for those who don't want to do fine pitch smd work themselves and before we have someone keen and willing to manufacture to our designs. At this point Tech Art = plug in CPU which is the main point of using it. It's very convenient for what we want to do.
Later anything is possible. I personally would like to see a microsquirt competitor out of this project as I just love small things of all sorts. Cam intends to design an SMD single board version for hand soldering also. The world is our oyster, but we need a rock to get started on ;-)
Fred.