[gta02-core] Board parameters update
werner at openmoko.org
Thu Aug 27 16:54:58 CEST 2009
Here's an update of the number of components we'll need and the structure
of the PCB:
- 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 ENIG
- For the board structure, we need input from the PCB factory. Openmoko
used a core of FR4 to which layers of PP 1080 65% and PP 1078 61% were
- PCB has components on both sides, about 10% on one, 90% on the other.
- Total number of components on the PCB will be about 400.
- Approximately 140 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 components are a 27 x 18 mm2 SIM/SD combi-cardholder, and a
22 x 22 x 3 mm3 BGA module.
- Largest chip is a 14 x 14 mm2, 0.5 mm pitch 332-FBGA (SC32442)
- Smallest component is 0402.
(*) I'd like to try to make this work with only 6 layers, but I'm not
sure if that's possible. Our circuit is considerably simpler than
Openmoko's, with a greatly simplified memory bus and GSM in a
module, so there is hope.
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