SACK V2 test
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:
> I transferred into wiki page and mapped with current some parts from Sharism
> inventory. So a rough V2 Bom cost is here now:
> 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?
Cel: +57 (300) 275 3666
Email: andres.calderon at emqbit.com
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> 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.
> if later having V3.
> 5, C69, C71: according to
> , 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
> 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
> 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.
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