On Thu, May 20, 2010 at 10:36 AM, Sebastien Lelong < [email protected]> wrote:
> Hi Vasile, > > 2010/5/20 vasile surducan <[email protected]> > > >> If ground planes could be OK, power supply route thickness could be to >> small (it is denitely too small for the power section of your design). >> > > At which point power supply routes become "normal" routes ? I mean I > understand routes coming from power supply need to be thick enough, but > while it supplies all the PCB, it'll become thinner and thinner, right ? I > guess it depends on components, is there any rule to compute thickness ? > > The basic rule is: - define aggressors (highest noisy, highest supply current), use all route to aggressors as short and as thick as possible, mount aggressors as closed to the lowest impedance point (which is the power supply) - define standard circuits, dimension the route size computing the current required for supply and the copper section (there are plenty trace calculators on the web) - define sensitive circuits (ultra high impedance amplifiers, very fast comparators etc) and route the supply trace in accordance with the circuit specific ( ultra high impedance needs route shielding, teflon isolation points, etc, very fast comparators are aggressors and need special care to keep low the power supply impedances near the IC, etc) - define RF circuits and use special RF technique for routing them > Power supply and ground routes must be treated as analog paths even for >> digital designs. >> > > Do you mean analog paths should be quite thick ? > Analog paths in the sense of analog input route in a a microcontroller does not need to be thick, however choose the size of an analog path at least double than for a digital (ie digital 10mil, analog 20mil). > Can you tell me more ? > not today, I'm already tired... > > > Cheers, > Seb > > -- > You received this message because you are subscribed to the Google Groups > "jallib" group. > To post to this group, send email to [email protected]. > To unsubscribe from this group, send email to > [email protected]<jallib%[email protected]> > . > For more options, visit this group at > http://groups.google.com/group/jallib?hl=en. > -- You received this message because you are subscribed to the Google Groups "jallib" group. To post to this group, send email to [email protected]. To unsubscribe from this group, send email to [email protected]. For more options, visit this group at http://groups.google.com/group/jallib?hl=en.
