Best way to deal with multiple power pins going to multiple component pins.
jwags818 , 11-22-2016, 04:13 PM
I am working on a schematic that has a digital camera chip on it. This chip has up to 5 pins that are the same power source at various locations around the perimeter of it. There is also decoupling caps required for each pin on this power net. Now I want the schematic to link the right caps to the right pins. There is a lot of them and if I make all the pins the same net then I will not know which caps go to which pins. So my thought was to give each chip pin of the same net a unique name. Example VPIX_PIN5, VPIX_PIN10 and VPIX_PIN84.
There is also a connector that brings power onto the board. It has 3 pins also for the camera chip power. If I wanted to leave these 3 pins just named VPIX. Could I then use a net label on the wire to tell which camera chip pin it goes to? And add a net tie so I can link them? What is the preferred method?
mairomaster , 11-23-2016, 02:16 AM
If all those pins on the IC/Connector are supposed to be connected to the very same voltage net, I would use the same net label for all of them - using net ties creates confusion and it's unnecessary in the vast majority of the cases.
With the capacitors you can do it in different ways. If it's not too messy, you can just connect each capacitor/capacitor group to the particular pin/group of pins directly, so it is obvious they need to be placed close to those pins.
If that creates too much of a mess, you can create groups of capacitors to the side and put a note next to each group with the pins they need to sit close to. Each group will be connected to ground and the voltage net label and not connected to the IC pins directly - that makes things clearer.
robertferanec , 11-24-2016, 09:33 AM
As @mairomaster explained, in the schematic, place the capacitors close to the pins where they should be and when you do PCB placement, be sure you place the proper capacitor close to the particular pin. This is how I have done it in schematics with hundreds of decoupling capacitors and it works well. You do not need to do anything else - using more net names would bring confusion.
When you do placement, open schematic on one monitor, open PCB on the other monitor and do it like this:
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