[gta02-core] Memory Schematics

Werner Almesberger 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 !

- Werner

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