PCB Review

[cksa]

Hi,

Over the past week i've routed up a new pcb (my 3rd ever one, first one using SMD components). Can anyone see any glaring errors/areas to re-examine before I send it off to manufacture?



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[cksa]

Note: Bottom left is a JST header "on top" of a regular 90 degree 0.1inch spacing header, this is so that I can populate one or the other, obviously not both at the same time!

[Zero999]

Can you post the schematic and the PCB source files?

It looks like Eagle which I have on my PC.

[cksa]

http://rapidshare.com/files/407966371/LEDpen.rar

It is eagle. This design is an RGB led controller, main input from two rotary encoders.

Thanks in advance.

[TheDirty]

What library are you using with the rounded SMD pads?  That looks nice.

Is that an RGB LED?  Make sure and double check the through hole size for the RGB LED leads.  They should be larger than needed.

I'm assuming you won't actually be soldering jumpers to the top jumpers.  If you are, they should have at least one pin spacing between them or some connectors might not fit on them.  Also it's nice to be able to just solder pins onto an edge connector like that and plug it directly into a breadboard for playing around with.

[Zero999]

http://rapidshare.com/files/407966371/LEDpen.rar

It is eagle. This design is an RGB led controller, main input from two rotary encoders.

Thanks in advance.

Why not just attach the files?

Click additional options, then choose, select the file you want and click ok. To add another file just click more attachments.

[cksa]

..trying out the attachment option now. thanks for letting me know!

The top jumpers aren't meant to have headers soldered onto them. The RGB led drill holes are 1mm, so it should be fine. The BIG RGB (4 pin header) up at the top is meant for the user to connect an RGB led through wires (i.e. for higher powered RGB led's) instead of directly soldering the rgb led onto the pcb.

[Zero999]

It looks different when I open it up, the filled planes are gone.

Could it be my Eagle settings?

All looks fine.

The only things I question are those resistor values. The current through the LEDs will be different because the forward voltage of different colours will be different. You also might not want them to be the same brightness, in my experience of colour LEDs, to make white, green needs to be brightest, followed by read, then blue. It's not a big deal, unless you're going to get 1000s built for you, as it's easy to change the resistor values afterwards.

[TheDirty]

It looks different when I open it up, the filled planes are gone.

Hit the ratsnest tool to fill in the polygons.  You can use the rip-up tool to clear them again.

[Zero999]

Thanks.

It doesn't save it though, it must be a bug.

[TheDirty]

Thanks.

It doesn't save it though, it must be a bug.

The default behavior of the polygon is to not be filled so whenever you load the board file you need to ratsnest if you want to see the board with the polygons filled.

[Zero999]

I've got a feeling that's going to annoy me, any way to change it?

[RayJones]

Looking at the schematic I was intrigued by VOUT_BOOST as I could not see where it comes from.

Then found pin 2 on the micro does not appear to connect to the trace near the first via properly...

[TheDirty]

I've got a feeling that's going to annoy me, any way to change it?

There's no way to change it that I know of, but that doesn't mean there isn't a way.  There might be something somewhere.

I prefer the polygons to be cleaned when I load the board.  Working with the polygon filled is a pain because your parts are lost in the plane of red or blue.  It doesn't dynamically adjust the polygon fill when you move parts around in it, so you need to hit ratsnest everytime you add or move anything to see what the updated plane looks like.  Usually you just fill the polygon every once in a while to make sure everything looks good then clear it again to actually work. 

[Zero999]

I prefer the polygons to be cleaned when I load the board.  Working with the polygon filled is a pain because your parts are lost in the plane of red or blue.  It doesn't dynamically adjust the polygon fill when you move parts around in it, so you need to hit ratsnest everytime you add or move anything to see what the updated plane looks like.  Usually you just fill the polygon every once in a while to make sure everything looks good then clear it again to actually work. 

Well I suppose, my favourite PCB software, Altium designer didn't automatically update planes either which I think would've been ideal, hopefully the latest version does. I'd personally like to save the polygon anyway because it means I don't have to faff around every time I open a file, simply because if I tell the program to save all my changes, it should damn well do it, not decide not to save parts because the developer thought it might be inconvenient for me which is th M$ approach.

[RayJones]

In Protel 99SE (the precursor to the Altium range) you have an option to hide polygons, fix up your artwork, then re-enable and re-pour.

If you had to always replace the vertices it would certainly drive me mad.

Can you do a simple global hide of polygons with Eagle?

[joelby]

In Protel 99SE (the precursor to the A!tium range) you have an option to hide polygons, fix up your artwork, then re-enable and re-pour.

Nowadays you can hide the polygons (though it's called 'shelving' - took me a while to figure that out).

I think it was pretty good about prompting you to rebuild them when necessary, but I find it much easier (for visibility reasons, and to avoid the prompt) to leave them hidden while fiddling with the design.

[TheDirty]

Can you do a simple global hide of polygons with Eagle?

I don't know of a way to globally clean polygons, but this is the kind of thing Eagle seems to be not good at, which is features that would be useful for very large and/or complicated designs.  I've never had a board with more than 3 polygons, so it's never been an issue for me.

[Zero999]

Wow, I didn't know about the hide polygons feature of Altium. I remember having to repour which wasn't too much of a big deal.

I've worked on a board with four polygons before, one was a ground plane which covered an entire layer, there were two analogue (+V and -V) which were on the same layer but spanned two solid blocks on either side of the board and a 5V digital supply which spanned another layer, apart for a small box at the edge, used for a DC-DC converter. Having a solid ground plane was convenient because it meant I didn't have to separate the analogue and digital grounds. The power supply planes were all unbroken apart from a few vias. It would've been handy if the CAD package I was using would have automatically adjusted the polygons as I edited the board.

[jahonen]

The most complex split power plane I have made on my personal projects must be this. digital +5, analog +5, -5, +15, -15 and digital +3.3 volt power distributed on one layer (those colorful areas). Needless to say that if PADS would not have flood priorities, it would have been quite difficult to do. They are also easy to hide and show (hiding reveals the pour outlines, so you can adjust them). BTW, this particular DAC-headphones amplifier is in use at this moment I write this

I used P'tel 99SE quite a lot in the past (before 2004 or so) (unpaid but hey, I was a poor student then! ), but got into the PADS later, since it is the de facto industry standard around here (not unpaid anymore!).

Regards,
Janne

[cksa]

Looking at the schematic I was intrigued by VOUT_BOOST as I could not see where it comes from.

Then found pin 2 on the micro does not appear to connect to the trace near the first via properly...

Thanks for the via spot.

VOUT_BOOST is supplied by the boost converter

Pads are rounded, created most footprints from scratch

[RayJones]

Looking at the schematic I was intrigued by VOUT_BOOST as I could not see where it comes from.

Then found pin 2 on the micro does not appear to connect to the trace near the first via properly...

Thanks for the via spot.

VOUT_BOOST is supplied by the boost converter

Yeah no problems, mistakes found earlier are always better before photo resist and etching takes place.

At work we often use a company that allows you to fill a 18" x 12" panel with whatever you choose, ie not all boards being produced need be the same.
Good for small foreign affairs 

Using Protel, we have sometimes accidentally made the mistake of re-pouring a polygon when it has been copied down onto the panel.
Since we no longer have a proper netlist for the GND connections, being so many individual boards, the pads end up remaining isolated from what should be a ground polygon without the connecting tracks.

This is a huge disappointment when you have waited a week or so to get your PCBs and then find such a user introduced error, usually after assembling one and you can't get it to go