[gta02-core] FYI: PCB/SMT parameters
alvieboy at alvie.com
Fri Jul 24 16:12:31 CEST 2009
Werner Almesberger wrote:
> For checking PCB making and SMT compatibility, I compiled this list of
> board parameters:
> - PCB size is about 10 x 6 cm2.
> - PCB has 8 layers, 1 mm overall thickness.
> - Minimum trace width is 4 mil, with a 4 mil clearance between traces
> and between traces and pads.
> - Surface finish is probably ENIG (need to confirm)
> - Not sure about the laminate.
> - PCB has components on both sides, about 10% on one, 90% on the other.
> - Total number of components on the PCB will be about 350-450.
> - Approximately 120-160 of the components on the PCB are unique.
> - There are about 20 components that don't have a standard chip
> package (connectors, buttons, shields, etc.)
> - Largest component is currently a 27 x 18 mm2 SIM/SD combi-cardholder,
> but we may add an LGA module of about 30 x 25 x 3 mm3.
> - Largest chip is a 14 x 14 mm2, 0.5 mm pitch 332-FBGA (SC32442)
> - Smallest component is 0402.
We will also need some other parameters, which depend heavily on the manufacturer, such as materials for conductor and insulator - thickness, dielectric
constant, loss tangent, relative permeability, conductivity.
So we can get the proper microstrip RF lines.
> I left a bit of wiggle room for the modem and such.
> - Werner
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