Footprint with vias in allegro

Status
Not open for further replies.
J

jayasree jayaraj

Junior Member level 1
Joined
Dec 22, 2020
Messages
17
Helped
0
Reputation
0
Reaction score
0
Trophy points
1
Activity points
128
Hi,
I am trying to create a footprint for LAN8742A-CZ-TR. I want to add vias in pads of footprint.I don't know how to create footprint with vias in allegro. Please tell how to create footprints with via using cadence allegro. i have attached datasheet of this component.
 

Attachments

  • DS_LAN8742_00001989A-1534922.pdf
    783.4 KB · Views: 222

Hi,
My doubt is how to add vias in footprint.I mean in .dra file how can we add vias?
 

Hi,
How to add thermal vias in thermal pad of footprints in allegro? Can you please suggest any videos or steps of adding thermal vias in footprints
 

Hello,

I have had the same issue before and I worked it out in a weird way but it was the only way that enabled me to do so.

First go to your schematic symbol and add pins with the same number of vias needed (you can make these pins invisible to avoid confusion).

Then go to your footprint and chose those pins as a via pad and place them where needed.

I have attached an example footprint, hope you find it useful.

If you do otherwise you will always get DRCs and bad connections, Good luck.
 

Attachments

  • to99.rar
    193.8 KB · Views: 191

Hi,
I did as per your suggestion.but as my thermal pad is smd and via is throughole i am getting drc error of thru pin to smd pin spacing.In my constraint manager i had set spacing of 0.127mm. I have attached my footprint below.
 

Attachments

  • LAN.zip
    13.1 KB · Views: 144

One way to do this is to create a smd pad of size 0.25*0.25 mm and place it in the middle of the pad, now create a shape that covers the heat pad, and place Via's in the shape. Remember large heat pads should not have 100% paste mask but rather a bunch of small areas summing up to 50-60%.
Another way to do it is to do a through hole pin, where bottom and inner layers are set to zero and instead of one hole do multiple in a pattern.
 

VIAs are not necessary while creating a footprint. Place a single/multiple Die-pad as you wish then place the VIAs while routing your PCB. Otherwise Netlist errors or Space Constraint errors occur
 

Adding vias in PCB design is an option, but Altium supports vias in footprint.
 

Status
Not open for further replies.

Similar threads

Menu
Log in
Register
Cookies are required to use this site. You must accept them to continue using the site. Learn more…