Davide said:
SSD voltage requirement ?
SSD current requirement (power value divided by voltage) ?
Enclosure power sources:
1) Via USB3 cable - 5V source
2) Via one or two heads of USB2 cable - 5V source
3) Barrel connector for 5V adapter in center of enclosure
http://download.fantec.de/Manuals/DB-228U3e/Fantec_Manual_DB-228U3e.pdf
SATA interface is 7 pins and 15 pins. 7 pins for data, not
an issue. 15 pins for power carries 3.3V, 5V, 12V. In a
desktop, 3.3V would be missing. In a laptop, perhaps just
the 5V is there for 2.5" drives. Most of the time, you
would be dealing with a 5V drive. Only in odd circumstances
(1.8" SSD microdrive?) do you find 3.3V drives. SATA hard drives
should be 5V powered.
You need to ensure a source of power, and with sufficient
current capacity.
That model of Fantec doesn't have ESATAp, as GMAN was describing.
That's another way to get power, only there is an issue with it.
http://www.delock.de/mail/esatap/esatap.html
Laptops with built-in ESATAp, are a source of 5V over ESATAp pins.
Desktops with built-in ESATAp, are a source of 12V over ESATAp pins.
The same two pins, can carry a different voltage, which is dangerous.
A 2.5" enclosure would likely need 5V. Connecting a 2.5"
enclosure to a desktop ESATAp would be dangerous, without
more information to go on. Could be a cloud of smoke.
So while it may look easy to buy an enclosure, there's a
small checklist to make sure it'll all work together.
The advantage of using a USB3 interface, is both power
and data are in the same cable. And the interface is
a standard, not a defacto half-designed standard like
ESATAp. USB3 has a higher current flow limit than USB2.
You could still profit though, from some knowledge of
the SSD. Some of the older SSDs had a peak power draw
of around 7W (5V @ 1.4A). Newer ones, the power is
minuscule by comparison, and for those, just about any
of the power sources mentioned above is sufficient. The
reason for drawing 7W, is significant processing (compression)
and flash data movement, to optimize wear leveling and
recover from 4KB random write tests. Some of the newer
SSD drives have such low power requirements, that I
don't believe the written specs when I see them. They're
that low.
If you have a model of SSD in mind, please post details.
That Fantec has both a USB3 connector and an ESATA connector,
and it's unclear to me, how the enclosure decides which
data connection to use. If the USB3 cable carries power to
the unit for ESATA operation, then the electronics are also
going to use USB3 to carry the data. To use the ESATA in an
unambiguous way, you'd need to plug in the barrel connector
of an optional 5V adapter. (The barrel connectors come in
fifteen different sizes by the way... Radio Shack carries them.)
USB3 power -----> enclosure uses USB3 protocol
USB3 data
+5V 1A adapter -----> enclosure uses SATA protocol
ESATA data cable
(Barrel connector standards - the enclosure should state
barrel dimensions to make selection easier.)
http://en.wikipedia.org/wiki/Adaptaplug#RadioShack_Adaptaplug_conversion_matrix
For me at least, buying these is not a ten minute job,
because so many details are left out.
And you do want them to work reliably. Remember, that an
SSD is less tolerant of powering problems - rip the power cord
out of an SSD while in mid-write, could leave the
SSD unusable. While we hope all operations inside
an SSD are "atomic", at least some enterprise versions
are equipped with a Supercap (energy storage device),
so they can properly flush the cache and maintain data
consistency. You should be a *lot* more careful with
an SSD in an enclosure, to think about stuff like that.
Do a "Safely Remove" in Windows, in the hope that all
operations are flushed before disconnecting.
Paul
