Howdy...

I have designed something of a "parallel port" for my 6809-based Tandy Color Computer using purely DIP packages which have 1/10th inch pin-to-pin spacing between the pins. I'm ready to print and etch using a transfer sheet, but I have no idea what the standard trace widths should be. Say maybe is it one half of that (.05 inch)? I don't know. Furthermore, is there any way to determine the necessary width of a PCB trace according to how much current it will have to carry? I'd appeciate some specifices. Thanks, and I'll be logging in here to find out and well as try to help others out.

Stephen

 

50 mils is a lot of trace for an I/O port. There is no actual "standard" for trace widths, though, so if you are able to use 50 mils, why not? I usually use 10 - 24 mils depending on the application and routing.

Have you made PCB's with these transfer sheets before? There may be some practical limit to the success of the process. We had a discussion on the subject in the Resources section.

If you know the thickness of the trace and its width, then you can calculate the cross-sectional area. You can then look you current handling for copper, although most of the data is for circular mils (one more conversion step).

 

Howdy...

I have designed something of a "parallel port" for my 6809-based Tandy Color Computer using purely DIP packages which have 1/10th inch pin-to-pin spacing between the pins. I'm ready to print and etch using a transfer sheet, but I have no idea what the standard trace widths should be. Say maybe is it one half of that (.05 inch)? I don't know. Furthermore, is there any way to determine the necessary width of a PCB trace according to how much current it will have to carry? I'd appeciate some specifices. Thanks, and I'll be logging in here to find out and well as try to help others out.

Stephen

For your signal traces using a transfer process I would use 12mil traces and a 50-60mil
pad. This will give you some process margin. If the pad is 60mils a 12 mil trace would
give you 14mils of space on either side of a trace that runs between pads.

(* jcl *)

 

Here's a handy chart - trace mil area vs temp rise vs current.