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A long article that says almost nothing. Instead of choosing trace widths and layer count and component sizes at random, take a week to read and understand the

A long article that says almost nothing. Instead of choosing trace widths and layer count and component sizes at random, take a week to read and understand the very useful book "High Speed Digital Design" by Howard Johnson. Despite the name it concerns itself more with the analog domain than with the digital. Very useful information about the behavior of traces and holes in boards.

pmorici 10y ago
I didn't want to be critical of it but as someone who went through the process of designing and manufacturing my own hardware product to sell a couple years ago that was my thought as well. Really long and very little insight into the real difficult parts.
- mng2 10y ago
  Yes, it seems much more like a high-level overview than an in-depth tutorial.
- jwr 10y ago
  As someone who has actually designed manufacturable boards I'd say the same. In addition the article has some strange recommendations: * don't use QFN — I see no reason to, on the contrary, these are great packages (see my other post in this thread) * 0603 minimum size for passives — huh? I see no reason not to go down to 0402, which is both easy to manufacture (assembly costs are the same, component costs are usually lower), and easy to prototype (just get a large desk magnifying glass and a good pair of tweezers and you're good to go).
tomkinstinch 10y ago
High Speed Digital Design is a great book (a "handbook of black magic," as its subtitle professes), and it is a nice complement to Horowitz and Hill's The Art of Electronics. You're exactly right that the former addresses way more analog details than the title suggests, and at high frequencies the analog stuff really matters. A passive component is never simply a capacitor, resistor, or inductor. We just call it one based on the dominant characteristic. At particular frequencies the characteristics can change so much that designs have to take the difference into account. Application notes and manufacturer references also contain a wealth of information. TI's Op Amps for Everyone (a great reference in general) has a chapter (17) devoted to PCB design: http://web.mit.edu/6.101/www/reference/op_amps_everyone.pdf http://web.mit.edu/6.101/www/reference/op_amps_everyone.pdf Beyond comprehensive references, you can pick up things from articles as you go; I learned the trick of using two back-to-back Schottky diodes to reduce the ground plane potential difference to <0.3V from a PDF like this one: http://www.ti.com/lit/an/slyt499/slyt499.pdf http://www.ti.com/lit/an/slyt499/slyt499.pdf Trade magazines with articles are another great resource, like Circuit Cellar or EDN.
bsder 10y ago
Johnson's book is good, but it is WAY overkill for the vast majority of PCB design that you can do as a hobbyist. I can sum up what you need to know for high speed design in a nutshell: 1) True high-speed design has a sample PCB layout in the datasheet or application note. Follow it RELIGIOUSLY. 2) If you don't have any specific notes about layout, put a single 50 Ohm resistor in series on any communication link clock line (aka JTAG-TCK, SPI-SCK, etc.) at the source. Too many chips these days are capable of launching and responding to a clock edge that has GHz components on a link that's supposed to be KHz. That 50 Ohm series resistor knocks the edge rates down to where they should be.

pmorici 10y ago

I didn't want to be critical of it but as someone who went through the process of designing and manufacturing my own hardware product to sell a couple years ago that was my thought as well. Really long and very little insight into the real difficult parts.

mng2 10y ago
Yes, it seems much more like a high-level overview than an in-depth tutorial.
jwr 10y ago
As someone who has actually designed manufacturable boards I'd say the same. In addition the article has some strange recommendations: * don't use QFN — I see no reason to, on the contrary, these are great packages (see my other post in this thread) * 0603 minimum size for passives — huh? I see no reason not to go down to 0402, which is both easy to manufacture (assembly costs are the same, component costs are usually lower), and easy to prototype (just get a large desk magnifying glass and a good pair of tweezers and you're good to go).

tomkinstinch 10y ago

High Speed Digital Design is a great book (a "handbook of black magic," as its subtitle professes), and it is a nice complement to Horowitz and Hill's The Art of Electronics. You're exactly right that the former addresses way more analog details than the title suggests, and at high frequencies the analog stuff really matters. A passive component is never simply a capacitor, resistor, or inductor. We just call it one based on the dominant characteristic. At particular frequencies the characteristics can change so much that designs have to take the difference into account. Application notes and manufacturer references also contain a wealth of information. TI's Op Amps for Everyone (a great reference in general) has a chapter (17) devoted to PCB design: http://web.mit.edu/6.101/www/reference/op_amps_everyone.pdf http://web.mit.edu/6.101/www/reference/op_amps_everyone.pdf Beyond comprehensive references, you can pick up things from articles as you go; I learned the trick of using two back-to-back Schottky diodes to reduce the ground plane potential difference to <0.3V from a PDF like this one: http://www.ti.com/lit/an/slyt499/slyt499.pdf http://www.ti.com/lit/an/slyt499/slyt499.pdf Trade magazines with articles are another great resource, like Circuit Cellar or EDN.

bsder 10y ago

Johnson's book is good, but it is WAY overkill for the vast majority of PCB design that you can do as a hobbyist. I can sum up what you need to know for high speed design in a nutshell: 1) True high-speed design has a sample PCB layout in the datasheet or application note. Follow it RELIGIOUSLY. 2) If you don't have any specific notes about layout, put a single 50 Ohm resistor in series on any communication link clock line (aka JTAG-TCK, SPI-SCK, etc.) at the source. Too many chips these days are capable of launching and responding to a clock edge that has GHz components on a link that's supposed to be KHz. That 50 Ohm series resistor knocks the edge rates down to where they should be.