nnewman
01-04-2002, 10:26 AM
Thought I'd pass on some more problems for your information.
in PPCB 4.0 when you convert to 250 layers some strange things can happen. I'm not sure of all of the problems, but my problem was that one of my vias connection a smd pad to power plane disappeared but the connectivity error check did not find it. The reason for this was that a thermal connection(without a pad or hole) was placed by PPCB on layer 2 where the power plane was and so a connection(?) was made. Actually every smd pad that had a via to a plane had a thermal connection under the pad.
Problem 2 - when I tried to change the pad/thermal size on the inner layers I ran into the pad size must be larger than the hole size, and 0 isn't larger than 0. Then I tried to edit the decal and found out that if I checked the thermal to see if they were 0, I could not get out of the edit mode because the spokes must be between 0 and 250, and 0 is not between 0 and 250.
The ultimate answer and work-around is to select "use global defaults" and not look at the thermals. use global defaults makes the thermals all 0.
Problem in CAM350 - a known problem for about 1 week. If you run an IPC-D-356A netlist out of PPCB (you need the new 4.7.2 software from Silicon Hills) you must select the single point net in CAM350's Utilities - Netlist extract. This assignes a net name to non connected pads and then checks for double net connections with the 356A netlist.
in PPCB 4.0 when you convert to 250 layers some strange things can happen. I'm not sure of all of the problems, but my problem was that one of my vias connection a smd pad to power plane disappeared but the connectivity error check did not find it. The reason for this was that a thermal connection(without a pad or hole) was placed by PPCB on layer 2 where the power plane was and so a connection(?) was made. Actually every smd pad that had a via to a plane had a thermal connection under the pad.
Problem 2 - when I tried to change the pad/thermal size on the inner layers I ran into the pad size must be larger than the hole size, and 0 isn't larger than 0. Then I tried to edit the decal and found out that if I checked the thermal to see if they were 0, I could not get out of the edit mode because the spokes must be between 0 and 250, and 0 is not between 0 and 250.
The ultimate answer and work-around is to select "use global defaults" and not look at the thermals. use global defaults makes the thermals all 0.
Problem in CAM350 - a known problem for about 1 week. If you run an IPC-D-356A netlist out of PPCB (you need the new 4.7.2 software from Silicon Hills) you must select the single point net in CAM350's Utilities - Netlist extract. This assignes a net name to non connected pads and then checks for double net connections with the 356A netlist.