[gta02-core] Memory Schematics
werner at openmoko.org
Mon Jun 22 02:30:30 CEST 2009
Luke Duncan wrote:
> This includes the updated symbol for the bead. Is there anything else that
> needs to be done for the memory schematics?
Thanks ! I've checked it in.
Bug (just one):
- the RPxxxx have no value
- Openmoko have RP2201 upside-down, which changes the pin numbers.
I think this deserves an ECN, small as it may be ...
Style (all of the issues are actually general):
- for the bead, its characteristics should be more interesting than
the part number (similar to what I said about varistors).
That KLB0603K601SA is a messy critter, though. The data sheet has
the following to say about it:
- KLB series
- 0603 size
- K means reated current is 800 mA
- 60e1 is the impedance (600 Ohm)
- S is the Standard series
- A means that there's no risk of lead poisoning
So far, so good. On the next page, we find KLB0603_601SA in the
table with the following properties:
- Impedance: 600 Ohm
- at 100 MHz (aha !)
- DCR: 0.45 Ohm
- Rated Current: 200 mA (???)
So ... why are there two currents ? Just a mistake ? At different
frequencies ? In the latter case, which is which ?
I looked at beads data sheets from TDK, Taiyo Yuden, and Murata,
and they all seem to be content with only one current.
- most of the caps should have placement constraints. We could either
indicate them visually by placing them next to the respective pins,
or add a comment that says where they should go. That will help
later, when doing the layout.
- also, please don't forget to X the unconnected pins
Thanks a lot !
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