Is there any way to insert a clearance constraint to avoid high voltage clearance violation between different layers.
As i see it must take into acount the layer stackup dielectric thicknesses and make angular geometric clearance calculation between different objects in different layers ?
Maybe any body uses a custom SKILL for that ?
What kind of voltages are we talking about? You may just have to find out what the dielectric withstand voltage of the pcb/prepreg material your are using is and adjust your board thickness / stackup accordingly.
STD FR4 is rated at 20kV/mm. Other pcb material maufacturers may have higher rated products. (Rogers comes to mind).
I know of no z-axis constraint other then identifying specific layers to route the high voltages on. Possibly alternate inner layers to increase the z-axis spacing.
In reply to TH Designs:
In reply to Robyd:
You really need to control z-axis by your stackup. Also, the IPC table does not apply to Z-axis spacing. See the earlier post.
UL 60950 latest edition will show you what the z-axis rules are. They have *recently* changed. If you run 3 cloths of pre-preg you can squeeze down. There are also tests that can be done as proof of compliance that will supercede any printed "rules"
50V spacing can *easily* be met by 2 mil spacing in z axis. Talk to your fabricator about what they can test to.
In reply to redwire:
redwire - thabk you for the reply
in IPC-2221 paragraph 6.3 you can find requirment for Z Axis i Quote
"6.3 Electrical Clearance : Spacing between conductors on individual layers should be maximized whenever possible. The minimum spacing between conductors....... layer to layer conductive spaces (z=axis), and between conductive materials ... and conductors shall be in accordance with table 6-1,....."
redwire :can you kindly share some examples of UL60950 clearance requirments fro PCB layout for Z axis ?
I understand that Allegro does not support Z axis clearance constraints .
About the 2 mil clearance being enough for 50V - this was only an example
BUT sometimes i have up to 1500 v and higher