SATA power for embedded widgets

Frnak McKenney <frnak@far.from.the.madding.crowd.com> wrote:
> If that were the only problem, you could download the schematic and
> Gerber files and cut some new almost-alike PCBs sans polyfuses.
> However, based on your comments above, that still leaves the board
> with binding posts which you'd then need to connect to your boards.
> Given that, I see why putting SATA connectors on your "widget" boards
> is a better solution.

Part of this is I really dislike hand-crimping Mini Fit connectors, which is
what I'd need to do to make a 'special' wiring loom (eg 24w ATX to umpteen
arbitrary-Mini-Fit connectors).  Obviously not a problem if you're making
vast numbers and can order the looms in volume, but more of an issue for
small volumes.  And why crimp if you can use the existing connectors?

> As to the SATA "signalling connectors": If you don't like the standard
> ones coming off the PSU, what would you prefer to have on your PCBs? I
> suppose you could put a 24-pin ATX connector on each instead, but I
> suspect that those would be a bit large. <grin!>
> 
> Ah, well.

Sorry, I should have been clearer.  More SATA male connectors are 22 way: 15
way part for power (3 rails * 3 pins each, 5 grounds, 1 reserved) and 7 way
part for data (2 twisted pairs, 3 grounds).

The PSU has 15 way connectors in the wiring loom.  These plug into the HDD,
and a separate cable from the motherboard goes to the 7 way data connector. 
If they're in drive bays, the drive mates directly with a 22 way connector
on the backplane that provides both parts.

So this means that any male connector has the data part included.  That
means there's a tempting SATA data socket that you just know users are going
to try to plug into their motherboard, even if you don't speak SATA
signalling at all.  It also wastes footprint on the board which you could
use for something else.

Hence the idea to just have the 15 way power part on the PCB to receive a
cable from the PSU, and no need for the 7 way data part.

Theo

On Tuesday, February 19, 2013 2:54:07 PM UTC-6, Theo Markettos wrote:
> Frnak McKenney <frnak@far.from.the.madding.crowd.com> wrote:
> 
> > If that were the only problem, you could download the schematic and
> 
> > Gerber files and cut some new almost-alike PCBs sans polyfuses.
> 
> > However, based on your comments above, that still leaves the board
> 
> > with binding posts which you'd then need to connect to your boards.
> 
> > Given that, I see why putting SATA connectors on your "widget" boards
> 
> > is a better solution.
> 
> 
> 
> Part of this is I really dislike hand-crimping Mini Fit connectors, which is
> 
> what I'd need to do to make a 'special' wiring loom (eg 24w ATX to umpteen
> 
> arbitrary-Mini-Fit connectors).  Obviously not a problem if you're making
> 
> vast numbers and can order the looms in volume, but more of an issue for
> 
> small volumes.  And why crimp if you can use the existing connectors?

You didn't really say how many of these you need, but if it's more than a few I would consider doing a simple power distribution board taking in the ATX, fusing for your slave boards, and then breaking out to a connector that you like or a set of screw terminals.  You can also do a low voltage power on switch and power indicator on there.