Interleaved some more.
On 11/13/2020 12:53 PM, Harvey White wrote:
Interleaved.
On 11/13/2020 1:11 PM, Dave wrote:
Harvey,
? I have a related question here after spending some time researching. I already have a bunch of JST XH connectors and plugs, and pins and the crimper.
Instead of JST, I use 0.1 inch spacing connectors.? The female/female jumpers can be tweaked to remove the individual shrouds, and can be reinserted in strip connectors to make some decent cables.? JST will work fine, but I've found them tricky to use.? I'd just as soon look for premade cables.? Your luck with the crimper (I hope) will be better than mine.
??????????? The .1 inch (2.54mm) spacing should work ok with the JST 2.5mm spacing, at least for short length stuff. SO I should be good there. I did look at premade cables but noticed nobody bragging about 100% copper and after researching deeper found most use copper clad aluminum. I hate that stuff as I need to cut the cables and solder one end elsewhere. I have had good enough luck with the JST crimping but have another crimper on my list to order.
I wanted to design a total SMT pcb and I could solder the power and ground wires to a pad. Then I thought about adding a JST header and use a plug for power and ground.
That works.
??????????? Except I don't have any SMT headers in JST XH and although they are available, they come in a 3 circuit style and a 4 and a 5. I really only wanted a 2 circuit version but I have that in a through hole and its also a 90 degree version to save some space on the enclosure height,.
Problem is, the JST parts are all through hole. So now for my question ( I may have a clue but will ask anyhow to verify ), what is the best method on the board design to use through hole and SMT at the same time?
I just put them in and let the router do its work.? For your design, you might want to have separate power pins if the supplies are different, say that if you need +5 for the top circuit and +12 for the lower one, have a power connector with separate pins for the two supplies.? That keeps the power supplies from being mixed.
??????????? I guess I was worried about the power feeding the top side while being soldered to the bottom side. I figured I had to have a jumper from the bottom back to the top but now that I think of it, the holes would be plated thru holes...
Will I still be able to do my planned 2 different circuits on either side of the board? How should I handle the power header? Use it to supply both sides of the board with one header or use 2 headers for power/GND and separate the copper with islands?
?Given a common ground for both circuits (which works), you're running separate supplies from separate pins, so just one connector and wire it appropriately depending on which circuit you're doing.? You can use unused parts of the other side as jumpers.? If you don't want to do that, you can use 0 ohm resistors (1206 works best just because of the size).? it's easier than running wire jumpers.
So yes, one power/signal connector can do the job if you think that the inputs/outputs don't make for too large a connector
If you have a lot of inputs and outputs, there's two ways to do this:
one is to have a separate power connector (and have separate pins for each supply rather than one "power" pin), and then separate connectors for each circuit.? I'd use different size connectors to avoid misconnections.
two is to have power and signals on one connector (perhaps few pins for signals) not sharing any pins except ground and identical power supply voltages.
??????????? I didn't even know they made "0" ohm resistors. But I am starting to understand it now. I guess I will start to design it and then in the software things will become obvious.
Thanks,
Dave
Harvey
Thanks,
Dave
