Author Topic: Here is my first board I designed in Altium as a trial.  (Read 493 times)

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Offline thomasb9511

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Here is my first board I designed in Altium as a trial.
« on: December 25, 2016, 07:50:12 PM »
Hey everyone,

I use Eagle for pcb work for school but I was advised to try Altium Designer for some of my more advanced circuits. Things are different but this ain't Eagle, and I enjoy Altium Designer much more for some reason.

This is a board I designed as an FTDI FT232RL breakout, any input would much appreciated. Nothing was auto-routed or auto-placed:
https://drive.google.com/file/d/0BxflnOkuXYUQOTRqQ2lhMFBkNTA/view?usp=sharing

One question, the fact that USB is a differential signal in this design, is it OK if the lengths aren't terribly matched? I did try to routed the differential as short as possible and length matching isn't happening when I try to use on those traces(it because of the shortness of the traces?)

P.S. the Google drive link is due the file size limits of the file uploader
 

Offline Fortran

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Re: Here is my first board I designed in Altium as a trial.
« Reply #1 on: December 25, 2016, 09:31:16 PM »
Looks pretty good.  :)
D1 and D2 are backwards, and I'm not sure if the reset pin can be floating.
Push some traces so they don't come off the pads in an angle.

No you don't need the USB to be length matched in this case.
The reason you can't get it to work is either that it's too short and constricted, or it's not properly set up. Length matching in Altium is black magic. It only seems to work when I don't know why.
You could however make those tracks 10mil too. Wider then the pads looks kinda off.
 

Offline thomasb9511

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Re: Here is my first board I designed in Altium as a trial.
« Reply #2 on: December 25, 2016, 10:00:28 PM »
RESET# can be tied to VCC or left unconnected if not being used. - per the manual
Would it still a good idea to tie up to VCC even though?
 

Offline Fortran

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Re: Here is my first board I designed in Altium as a trial.
« Reply #3 on: December 25, 2016, 10:27:59 PM »
If the datasheet says unconnected is fine, then it's just fine as is. :)
Not all IC's like floating resets though, so a mindset of always pulling it to its intended state might save you some headache in a different project.
 

Offline thomasb9511

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Re: Here is my first board I designed in Altium as a trial.
« Reply #4 on: December 25, 2016, 11:18:10 PM »
On a side note, if something is active low like the reset pin on most ICs it means low effectively turns on the the reset circuit, right?

Also here is an updated zip: https://drive.google.com/file/d/0BxflnOkuXYUQSlFrbGtubm1ZcVk/view?usp=sharing
 

Offline Fortran

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Re: Here is my first board I designed in Altium as a trial.
« Reply #5 on: December 25, 2016, 11:47:26 PM »
Correct.
Active low are usually typed as #RESET, RESET# or with an overline.
In Altium, you can do the overline by putting \ after each letter, R\E\S\E\T\
 

Offline Fortran

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Re: Here is my first board I designed in Altium as a trial.
« Reply #6 on: December 26, 2016, 12:03:25 AM »
Also here is an updated zip:

Yes that looks a lot better.
You could also move the VCC33 a bit further from VCC to connect the ground. (Between DSR and RTS)
 

Offline thomasb9511

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Re: Here is my first board I designed in Altium as a trial.
« Reply #7 on: December 26, 2016, 12:31:58 AM »

Yes that looks a lot better.
You could also move the VCC33 a bit further from VCC to connect the ground. (Between DSR and RTS)
This? Where the arrows are?
or the island?
« Last Edit: December 26, 2016, 12:34:30 AM by thomasb9511 »
 

Offline thomasb9511

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Re: Here is my first board I designed in Altium as a trial.
« Reply #8 on: December 26, 2016, 12:47:29 AM »
« Last Edit: December 26, 2016, 12:59:30 AM by thomasb9511 »
 

Offline Fortran

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Re: Here is my first board I designed in Altium as a trial.
« Reply #9 on: December 26, 2016, 01:21:51 AM »
Yes the last one is what I meant.  :-+
 

Offline technotronix

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Re: Here is my first board I designed in Altium as a trial.
« Reply #10 on: January 14, 2017, 09:29:52 PM »
Yes, It is true. Nice design.  :-+
 

Offline blueskull

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Re: Here is my first board I designed in Altium as a trial.
« Reply #11 on: January 14, 2017, 10:06:16 PM »
1. USB length mismatch is okay for full speed designs, not a big deal.
2. Your spacing is 5 mil, which is a bit small for most fabs. Many fabs require 6 mil min. track width and spacing.
3. No input fuse.
4. L1 may or may not be necessary, depending on EMI requirement and length of cable.
5. Whenever possible, add at least one grounding via per decoupling cap's GND pad (same for high speed ICs).

Other than these, this is a nice design.
SIGSEGV is inevitable if you try to talk more than you know.
 

Offline stefanh

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Re: Here is my first board I designed in Altium as a trial.
« Reply #12 on: January 18, 2017, 02:31:00 PM »
The fiducials and polygon clearance are a bit small. 

I would generally make the pad 1mm in diameter and allow 1mm clearance all around. Also I would only put three of them on the PCB corners to help prevent the board being rotated 180 degrees assuming it was to be machine loaded.

There are many other fiducial best practices that can be searched for.
 


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