SACK V2 test

Andrés Calderón andres.calderon at emqbit.com
Tue Jul 27 07:52:56 EDT 2010


On Tue, Jul 27, 2010 at 5:14 AM, Adam Wang <adam at sharism.cc> wrote:
> 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.
>

How much the 32 MBytes  SDRAM?

The FPGA is by far the most expensive component, can be replaced by
XC3S100E or XC3S250E?

    Andrés Calderón
    Cel:     +57 (300) 275 3666
    Email: andres.calderon at emqbit.com
    Gtalk:  andresfcalderon at gmail.com
    Web:    www.emqbit.com


> 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.pdf
> if 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 as
> listed.
>   7. D8/D9: CDBU0130L 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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