SACK V2 test

Adam Wang adam at sharism.cc
Tue Jul 27 06:14:34 EDT 2010


Hi David & Carlos,

According to your V2 bom:
http://downloads.qi-hardware.com/hardware/sakc/bom/rc2/sakc_V2_BOM_carlos_0723.ods
I transferred into wiki page and mapped with current some parts from Sharism
inventory. So a rough V2 Bom cost is here now:
http://en.qi-hardware.com/wiki/SAKC_RC2_BOM
They p/n or price will undergo changes even before the PCB prototypes are
fabricated. It's still without USB cable & box.

Here's my comments:
a) Are you really need a 64MB 512Mb SDRAM? Why not 32MB same as BEN? Surely
we know the bigger the better. Pls see its cost carefully.

b) Parts:
  1, D10, from http://en.qi-hardware.com/w/images/b/bf/SAKC.jpg, seems you
removed the diode on the led drive board I sent to you then soldered on V2
board. You can check and try to use MSCD104H used on BEN or AVT2. I filled
it in "Substitution P/N" column.Check it if it can meet your footprint.
  2, C15, 10nF on schematic, you want it 100nF or 10nF?
  3, R2, 2.5k/1% on sch.; actually it will be mounted a 2.49k/1%.
  4, Y3, it's FXO-HC536R-50 (5.15mm * 3.35mm) on bom, but should use
FXO-HC736R-50 (7.5mm * 5.2mm) to meet your footprint. I suggest that we can
use smaller one: SO5032-050000-O3A-BBE-QA  which is used on Milkymist One
even later Xue.
http://downloads.qi-hardware.com/hardware/sakc/datasheet/Y3~SO5032-050000-O3A-BBE-QA~NOT_FINAL.pdfif
later having V3.
  5, C69, C71: according to
http://downloads.qi-hardware.com/hardware/qi_avt2/v1.0/datasheet/LCM~GPM940B0-SPEC_A_2009.01.13~~FINAL_LCM-NOT_ON_SOME_PROTOTYPES~~.pdf,
those two are suggested to be 4.7uF/25V, but they are all changed to
4.7uF/16V. You can easily check those body color are likely different on
BEN's led driver board compared to others capacitors. I'll directly change
them later.
  6. J6/J7/J18: those three actually can combine into one part
MD241845<http://www.stm.com.tw/test/pdf-1/c24184.pdf>as listed.
  7. D8/D9: CDBU0130L<http://www.comchip.com.tw/cms/UserFiles/QW-A1107-CDBU0130L-RevA134692.pdf>this
Schottky Barrier Diode 100mA 35V, if you don't insist, pls ref. to use
MSCD104H same as AVT2 & BEN.
  8. 10V, 10uF, 10%: I use TANTALUM capacitor (our inventory) instead of
MLCC.
  9. L13: I'll temporarily use PI0302-4R7M if I don't have it before smt.
  10. R34: once you finish test charge function, pls tell me the value.

c) Layout:
   1. J20: LCM FPC connector, As same Wolfgang questioned its orientation
previous reply.
   2, L12: let it not close to U11 body.
   3, J19: mark "J19" reference on silkscreen.

All above can be as next change reference. Pls let me know your thinking on
above items.
Thanks,
Adam
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