[SI-LIST] Re: USB drive Current Consumption

USB specifies two power classes: 500ma and 100mA. All devices have to
power up at 100mA max. During enumeration the device makes its class
known and the host can decide to enable or not. Usually, most PC host
controllers are capable of 500mA, whereas many hubs have a 100mA limit.

Mike

-----Original Message-----
From: si-list-bounce@xxxxxxxxxxxxx [mailto:si-list-bounce@xxxxxxxxxxxxx]
On Behalf Of olaney@xxxxxxxx
Sent: Wednesday, June 17, 2009 10:53 AM
To: vivek8419@xxxxxxxxx
Cc: si-list@xxxxxxxxxxxxx
Subject: [SI-LIST] Re: USB drive Current Consumption

500 mA is the generic USB spec limit.  There are so many flash drive
variants that no rule of thumb will suffice.  If you want typicals, it's
cheap and easy to cut into a USB extension cable and make measurements
yourself.  However, I suspect that few memory sticks approach the limit
on other than a transient basis.  They would run noticeably hot if they
did, and I've never encountered that.  Let the list know what you find
out.

Orin Laney

On Wed, 17 Jun 2009 18:57:50 +0530 Vivek Kumar <vivek8419@xxxxxxxxx>
writes:
> Dear All,
> 
> What is the worst case current consumption of a USB pen drive from 
> 5V
> USB bus across various memory capacities?
> 
> Most of the links over th web says its 500mA max.
> 
> Please throw in your thoughts.
> 
> Cheers
> Vivek
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