Author Topic: Equal length fanout  (Read 1842 times)

0 Members and 1 Guest are viewing this topic.

Offline blueskullTopic starter

  • Supporter
  • ****
  • !
  • Posts: 367
  • Country: cn
  • BA7LKP
Equal length fanout
« on: October 31, 2016, 09:06:32 am »
How do you do equal length fanout in AD? I'm not asking for length matching between nets of the same class. I'm asking for fanning out signal of same net from a common source to different locations.
I do not want to touch xSignals unless necessary. I only have 4 nets need this kind of delay matching, other nets are not delay sensitive.
 

Offline T3sl4co1l

  • Super Contributor
  • ***
  • Posts: 21686
  • Country: us
  • Expert, Analog Electronics, PCB Layout, EMC
    • Seven Transistor Labs
Re: Equal length fanout
« Reply #1 on: October 31, 2016, 01:52:44 pm »
So it's not really a matched net length, but a matched subnet length?  Should you be using From-Tos?  Or a clock distributor or buffer to minimize the mismatch at the source?  (Yes, the buffer itself may have much worse delay matching than your PCB layout, making that a silly solution.  On the other hand, if it has to be that precise, surely you're screwed regardless, and some means of fine adjustment will be necessary anyway?)

Anyway, there's an example in the Altium docs of using a net bridge to fan out symmetrical delays.  That's another option. :)

Tim
Seven Transistor Labs, LLC
Electronic design, from concept to prototype.
Bringing a project to life?  Send me a message!
 


Share me

Digg  Facebook  SlashDot  Delicious  Technorati  Twitter  Google  Yahoo
Smf