Good practice for reducing and controlling noise in circuits

[paulr]

Hi. Every time I look at a professionally designed circuit I'm struck by the number of components and features apparently only there to control noise. As an
amateur with experience mostly in digital electronics, managing noise has always seemed something of a black art to me.

When I design circuits I'm concerned I may be missing important noise-controlling features, so that even if my circuits work ok on the benchtop, they may malfunction 'in the wild'.

Areas of ignorance for me include:

Shielding cables - when it's necessary and what to connect the shield to
RC filters on digital inputs
Decoupling capacitors - where, how many and what values
Separate analog/digital/power grounds
...and I'm sure plenty of other situations I'm not even aware of.

Can anyone recommend any websites, rules of thumb, or tutorials for information on matters like this? If you've found any sources particularly useful in getting to grips with noise, I'd be interested to hear about them. Thanks.

 

[cowboybob]

You might start here:

https://ww1.microchip.com/downloads/en/DeviceDoc/21975b.pdf

 

[paulr]

Thanks, there's a lot there, I'll take a look.

 

[dr pepper]

Commercial electronics are designed to meet various guidelines so manufacturers go to lengths to make sure they conform, esp when they are making 1000's off production runs, one offs made in the home lab dont necessarily need to comply exactly to these, however you need to know enough to ensure what you build doesnt interfere with itself of those around you.

I recently had trouble with a rs232 driver ic, noise from the supply was so great it was causing the data to corrupt.

 

[misterT]

..managing noise has always seemed something of a black art to me.

It is a black art. There is a book called: High speed digital design: A handbook of black magic.
That is a great book. It may help you understand some things.. or maybe confuse you more