SSD power requirements question

[crmaris]

Does anyone know for sure from which rail(s) an SSD draws power?
I think that the 3.5" SSDs draw from 5V only and 1.8" from 3.3V but just want to be sure, for my next project

[Tator Tot]

Since they're SATA products you can't say that this is the way that all of them will be made, but you're correct:
2.5" / 3.5" SSD's (any of the last two generations at least) draw power on from the 5v rail
1.8" SSD's draw power from the 3.3v or 5v depending on the SSD at hand.
mSATA / mPCIe all use the 3.3v rail

Still, all of their power draws are insignificant at best.

[Original Sin]

2.5"/3.5' drives draw 5v only... mPCIe drives draw 3.3v.

[crmaris]

thanks for your answer guys. A plain HDD draws from 5V only or it uses 12V too? In case I want to measure power consumption on some of these too.

[rafal_iB_PL]

HDDs draw power from 12V too, for mechanics. 5V is for electronics.

[crmaris]

thanks. I knew something was going on with +12V in them but just wanted to be sure. So I will go only with SSDs since I want to use a single shunt and avoid the fuss.

[McSteel]

- All 3.5" HDDs draw 5V for electronics and 12V for spindle and arm motors.
- Some 2.5" HDDs also draw from 12V (but all of them are high-performance drives, such as Velociraptors and some 7200+ rpm models)
- Most 2.5" HDDs make do with just 5V for both electronics and mechanics, especially the slower rotating ones (5400 rpm or less)
- Almost all 1.8" HDDs draw 3.3V for both mechanics and electronics, though there are some mSATA models that also take 5V, but they are very rare.

As for SSDs, none of them require 12V, and only some of them (mPCI-E, mSATA) require 3.3V, since most SSDs are made to be compatible with the 4-pin Molex -> 15-pin SATA power adapter.