Courtyards

[ltrakal]

What do you guys use as a default spacing between pads of a part and its courtyard? I found in the cd that we can snap to 0.5 mm but that rule doesn't apply for res and caps?

Laszlo

[randychase]

There will be more info on this subject soon.

[Tom]

Laszlo,

I'm attaching a file that we got at the last APEX (IPC) conference that defines courtyard sizes. It actually defines pad sizes too.

You should have an IPC-SM-782 book handy because this document refers to chapters in that book.

This single document defines the 3-Tier library system and the courtyard sizes and tolerances for each level (Least, Nominal & Maxium environment use).

[ltrakal]

thanks a lot tom

Laszlo

[Lameris]

Is the courtyard located on Layer 20?

[Tom]

Yes, all placement courtyards are on Layer_20 with a 0.1mm line width.

[Mark Larson]

Do you take into account, or suggest, a body to body dim under setup-design rules? PowerPCB will check that your courtyards don't overlap, but I have found that making the outline on L20 to represent the actual courtyard and then set body to body = 0 yields false errors under verify design when you place comps "line to line" Seems that you might want to decrease the outline on L20 to accomodate the body to body setting. But I've also found the courtyard screws up DFT Audit when you have comps and test points on the same side. When making a comp outline you have to consider the DFT Audit setting for probe to body.

Comp outline seems to be one of the more complex aspects in PowerPCB, at least to do it right if you intend to use all features.

[Tom]

Mark,

You are absolutely correct in your assessment of Placement Courtyards and Layer_20.

PowerPCB DFT Audit option currently identifies Placement Courtyards as "Component Bodies" and will not allow the placement of a test point on the courtyard, but we "The Users" want to place test points on courtyards. If the User places a test point on a courtyard, DFT Audit will flag it as a placement error. This problem has been around for years and needs to be fixed.

This has been a wish list item for a while.

If you set Setup/Design Rules/Default/Clearance/Body to Body to Zero, it will create false errors. In order for courtyards to work properly you must put a value in the box. I use 0.05mm.

Innoveda needs to offically assign a "Placement Courtyard" layer. So far to my knowledge, Innoveda does not have any documentation on placement courtyards nor do they have any offical layer assignment for them.

We use Layer_20 because it was the last available electrical layer and we thought that by using an electrical layer we could take advantage of DRC. What happens when you open up the extended layers? Layer_20 goes to Layer_120. Do courtyards still work? I haven't opened the 250 Layer Scheme yet to check it out.

In January 2002, we have pulled the courtyard back by 0.05mm on all SOIC's, QFP's & BGA's just so that when you place the parts using a 0.5mm grid system the courtyard edges do not touch or overlap. This will produce a clean DRC.

What IPC states in the IPC-SM-782 that courtyards should snap to a 0.5mm grid for those large parts and 0.1mm grid for the small parts and that the courtyard should be allowed to bump without DRC errors. I don't know how to make the PowerPCB software allow that. The courtyards cannot bump or overlap without causing DRC errors.

Note: Some PCB designers think Placement Courtyards are unnessecary because they are highly skilled in the art of "Part Placement". But Placement Courtyards are a nice feature to have in a CAD library. Whether you use them or not is personal preference. Placement Courtyards on Layer_20 can easily be turned on or off.

[Mark Larson]

I think Innoveda would claim that layer 20 is the courtyard layer, after all, you can place an outline there and use nudge to place (I said you can, it's too painful to me) or verify design to check that "courtyards" do not violate (assuming your body to body distance isn't 0). I don't jnow what the message icons mean, but I'm giving Innoveda the thumbs down on component outlines, it's not real bad, but it could use some work. Or at least some sort of explanation on how it's supposed to work. I get the impression it's a work in progress.

[Tom]

Mark Wrote:
I get the impression it's a work in progress.

My observation has been that Innoveda has been very quiet the past couple of months, not really saying a lot about anything. I've got several issues in Tech Support right now without an anwser. I've sent them a recommended extended layer plan with no response. No one has a clue on when a V4.0.1 Service Pack will be available. Release V5.0 features are vague and not public knowledge and the release date is unknown. For the first time since I can't remember Innoveda (PADS) is not advertising anything in PCD Magazine this month. This is when I'm used to seeing Hyperlynx, CAM350, Blazerouter and PowerPCB all simutaneously advertised in the same monthly issue for years. It's not the same old PADS Inc. that we once knew.

I guess we'll have to wait until the International Innoveda User Group Conference to get our questions answered.

[randychase]

After receiving a request for me to renew my maintenance and a 10% off if I did it with a credit card by the 30th of last month, I wonder about that. Seems short sighted to lose 10% to get cash now, unless you are in a cash flow crunch. I expect they took a hit from the downturned economy and Sept 11th.

Stock has dropped more also. Last I saw was at $1 a share.

[Mark Larson]

Most everybody is having cash flow problems, the company I was working for couldn't spend money fast enough a year ago, this year they are in a money crunch, one of the results is they raised the price of soda in the vending machines 25 cents! Last year they sent 6 people to the UG, this year nobody was going before the event was postponed, I was paying out of my own pocket. Companies are adjusting thermostats, ending janitorial service, shutting down between Xmas & New Year without pay, putting raises on hold. It's no wonder Innoveda is pinched, I doubt many companies are buying CAD software right now. One of the big reasons to buy software is when you add new employees, and that aint happening much right now. In Mpls./St Paul Innoveda gave us an AE and a sales guy last summer, only to take them away a couple months later. The squirrels that were storing some of their nuts instead of eating them all are sitting good, but for the rest it's a brutal world.