Dr L.: I read your post on the OrCad forum and it looks like you need some good PCB stackup consulting. Talk to your fabricator or hire a consultant to help you. That stackup is not reliable and will produce some noise/crosstalk issues.
Regarding the products. The basic package includes a signal layer routing limitation of 6 layers. Your stackup would not qualify unless you turned off routing on top and bottom.
Specctra is the name of the pcb autorouter from older days -- it remains basically unchanged but renamed in the newer products called PCB Router.
Allegro L will get you more constraint capability but it won't increase layer count. That is a different product "Router Performance"
I have been on the product for more than 15 years and have not *truly* needed the additional routing layers. There are some tricks you can play by turning off routing layers but 6 signal layers covers a *lot* of pcb designs. Power planes and stackup play an important part and contribute to the high layer count like your reference design has.
Here is a link to the Cadence datasheet: http://www.cadence.com/rl/Resources/datasheets/7432_PCB_Designs_FINAL.pdf
In reply to redwire:
In reply to DrLightning:
Working from #4 on your reply backwards.
The stackup? You posted it:
Here is the detail of the reference design layers:
4 signal layers (ML4, ML5, ML6, Bottom) is not consistent with good signal integrity and power integrity practice. 11 layer boards are not standard. Check with your fabricator and / or hire a specialist.
#3) The tricks are complex to write out in one sentence to a newbie on a forum. I'd suggest practicing with the tool for a while and ask specific questions.
#2) No. Router Performance is an option. Perf. L gets you constraints.
#1) 6 signal layers is 6 signal layers. Power planes don't count no matter how hard you try.
just to #1)
- you would place the parts by hand
- you will decide about the stackup of the board (brainwork in collaboration with your boardshop)
- you will fanout (automatically or by hand) just the GND and PWR nets (that means 4-6 layers are done)
- now you disable the done nets from routing and you autoroute the last 4 - 6 layers, that means your actually autorouter will be fine...
Thats the way I understand redwires posts.