Thermal Relief For Through Hole Padstack

[fraimdp]

padstack thermal relief

From **broken link removed**..

"Thermal Relief – The Power Plane Thermal Relief has five attributes. Thermal Relief’s have an outside diameter, an inside diameter, a spoke width, a spoke rotation and 2 or 4 spokes. The Outside Diameter is typically the same size as the Anti-pad. The inside diameter is typically 80% less than the outside diameter. The spoke width is typically 4 times smaller than the outside diameter with 4 spokes or 3 times smaller than the outside diameter with 2 spokes. The spoke rotation is normally 45 degrees with 4 spokes. All Thermal Relief feature sizes are in increments of 0.05mm."

What are the standards for five spokes thermal relief? Are there any sources for designing thermal pads? Please help. Thanks

 

[House_Cat]

ipc 2222 thermal relief

The standard for thermal reliefs is published in IPC-2222, section 9.1.2. Using the sample calculations, you can figure out the proper dimensions for a 5 spoke relief.

See forum item:

 

[fraimdp]

padstack

Hi.. im kind of new here.. i dont have enough points to download the IPC 2222 standard. How can i earn them quickly? thanks very much.

 

[echo47]

ipc thermal relief

Hi fraimdp, the page with IPC-2222 has a "free mirror" link that requires no points. The free mirror server may be busy and slow, so be patient.

Here's info on the points system, including several ways to increase your points:
https://www.edaboard.com/points.php

 

[abhi002]

Hi House_Cat and Fraimdp,

Is there any provision for single spoke thermal relief.

DO u use,if so what are the advantages and disadvantages?

I am curious to know?

Regards,
abhi

 

[House_Cat]

I've never seen a single spoke thermal used on a board. The disadvantages would be increased impedance to the plane from the via or pad, and increased possiblity of breaking the connection because of reduced strength.

Remember that the ONLY reason for a thermal pad is to make soldering easier. A via or pad that is directly connected to a plane represents a very efficient heat sink when trying to solder a connection. By reducing the amount of copper connected to the via or pad, you make it easier to heat the joint for soldering and unsoldering. There's no need to get carried away with the reduction - a four spoke thermal works very well in most applications. A large hole such as used for connector mounting might work better with a two spoke thermal because of the higher heat needed to solder the larger connection.

 

[abhi002]

thanks for the information.

its really helpful

 

[juggernaut7]

I agree with House Cat. You can get a more robust connection to the plane merely by increasing the width of the spokes. I sometimes route a fat trace on the top side and drop it to the plane with two vias that don't have thermal relief. That way I get both thermal relief and a solid plane connection.