A Sandisk 64GB mini. "Ultra Fit"

All thumb drives heat up when operating, but why to they heat up and
remain so when plugged in and idle?

Peter Jason wrote:
> A Sandisk 64GB mini. "Ultra Fit"
>
> All thumb drives heat up when operating, but why to they heat up and
> remain so when plugged in and idle?
>

I've a few(more than I really need) SanDisk thumb drives, the only one
that gets a bit warm when plugged in and not operating is a 32 GB
SanDisk Cruzer Orbit.
- not warm enough to be considered too warm or hot, but noticeably
above ambient temperature.

--
....w¡ñ§±¤ñ

On 10/11/2023 9:04 PM, Peter Jason wrote:
> A Sandisk 64GB mini. "Ultra Fit"
>
> All thumb drives heat up when operating, but why to they heat up and
> remain so when plugged in and idle?
>
It's a plastic barrel USB stick.

I hate those, because I managed to snap a pin
inside the plastic barrel of a Lexar 128GB, the first day of using it.

With a plastic barrel, there is no thermal path to use
the chassis for some cooling.

The metal barrel, controls the relation of contacts to barrel,
for a better quality of capture during plugin. Reducing the
chance of snapping pins.

And yes, someone did notice your heat problem :-)

https://forums.sandisk.com/t/ultra-fit-usb-3-0-excessive-heat/33099

"In addition, I measured the current drawn by the Ultra Fit USB 3.0,
it is more than 4x higher than the current drawn by the Cruzer Fit USB 2.0.

Ultra Fit USB 3.0 = 896 mA

Cruzer Fit USB 2.0 = 200 mA

Could this be the reason of the overheat, considering the physical size
is not much larger while the power has increased 4 times.
"

You can buy little USB multimeter things, that read out voltage
and current on USB ports, and that would be an ideal way to repeat
the measurement that poster made. I don't have one of those.

So yes, four and a half watts in a package the size of your thumb. Yikes!
That's more power than any of the individual SSDs I own.

I would need to see multiple people measure this for me, to
believe such measurements. That 896 number is "suspicious".
Someone needs to give me a range, like did the number vary,
and by how much. Then I might believe that's a functional current.
While bypass caps can short out, it's unlikely that the problem
would produce such an exact number like that. 5V @ 900mA is the
USB3 intended design limit. The fuse does not cut off at that
point, but allows even more current than that.

Paul

On 2023-10-12 13:17, Paul wrote:
> On 10/11/2023 9:04 PM, Peter Jason wrote:
>> A Sandisk 64GB mini. "Ultra Fit"
>>
>> All thumb drives heat up when operating, but why to they heat up and
>> remain so when plugged in and idle?
>>
> It's a plastic barrel USB stick.
>
> I hate those, because I managed to snap a pin
> inside the plastic barrel of a Lexar 128GB, the first day of using it.
>
> With a plastic barrel, there is no thermal path to use
> the chassis for some cooling.
>
> The metal barrel, controls the relation of contacts to barrel,
> for a better quality of capture during plugin. Reducing the
> chance of snapping pins.
>
> And yes, someone did notice your heat problem :-)
>
> https://forums.sandisk.com/t/ultra-fit-usb-3-0-excessive-heat/33099
>
> "In addition, I measured the current drawn by the Ultra Fit USB 3.0,
> it is more than 4x higher than the current drawn by the Cruzer Fit USB 2.0.
>
> Ultra Fit USB 3.0 = 896 mA
>
> Cruzer Fit USB 2.0 = 200 mA
>
> Could this be the reason of the overheat, considering the physical size
> is not much larger while the power has increased 4 times.
> "

There is no doubt whatsoever that is indeed the reason it heats up!
Gosh. If it draws almost one amp at 5 volts, it certainly will heat up.
It is 4.5W

The question is instead why does it draws 900 mA.

> You can buy little USB multimeter things, that read out voltage
> and current on USB ports, and that would be an ideal way to repeat
> the measurement that poster made. I don't have one of those.
>
> So yes, four and a half watts in a package the size of your thumb. Yikes!
> That's more power than any of the individual SSDs I own.

5 W.

Some car bulbs are 5W. You can easily compare.

> I would need to see multiple people measure this for me, to
> believe such measurements. That 896 number is "suspicious".
> Someone needs to give me a range, like did the number vary,
> and by how much. Then I might believe that's a functional current.
> While bypass caps can short out, it's unlikely that the problem
> would produce such an exact number like that. 5V @ 900mA is the
> USB3 intended design limit. The fuse does not cut off at that
> point, but allows even more current than that.

The figure is not weird at all :-)
The specs would say something nice like 5V @ 900mA, but any actual
measurement fluctuates and will never be a nice figure.

--
Cheers,
Carlos E.R.

Paul <nospam@needed.invalid> wrote:
> On 10/11/2023 9:04 PM, Peter Jason wrote:
> > A Sandisk 64GB mini. "Ultra Fit"
> >
> > All thumb drives heat up when operating, but why to they heat up and
> > remain so when plugged in and idle?
> >
> It's a plastic barrel USB stick.
>
> I hate those, because I managed to snap a pin
> inside the plastic barrel of a Lexar 128GB, the first day of using it.
>
> With a plastic barrel, there is no thermal path to use
> the chassis for some cooling.
>
> The metal barrel, controls the relation of contacts to barrel,
> for a better quality of capture during plugin. Reducing the
> chance of snapping pins.
>
> And yes, someone did notice your heat problem :-)
>
> https://forums.sandisk.com/t/ultra-fit-usb-3-0-excessive-heat/33099
>
> "In addition, I measured the current drawn by the Ultra Fit USB 3.0,
> it is more than 4x higher than the current drawn by the Cruzer Fit USB 2.0.
>
> Ultra Fit USB 3.0 = 896 mA
>
> Cruzer Fit USB 2.0 = 200 mA
>
> Could this be the reason of the overheat, considering the physical size
> is not much larger while the power has increased 4 times.
> "
>
> You can buy little USB multimeter things, that read out voltage
> and current on USB ports, and that would be an ideal way to repeat
> the measurement that poster made. I don't have one of those.
>
> So yes, four and a half watts in a package the size of your thumb. Yikes!
> That's more power than any of the individual SSDs I own.
>
> I would need to see multiple people measure this for me, to
> believe such measurements. That 896 number is "suspicious".
> Someone needs to give me a range, like did the number vary,
> and by how much. Then I might believe that's a functional current.
> While bypass caps can short out, it's unlikely that the problem
> would produce such an exact number like that. 5V @ 900mA is the
> USB3 intended design limit. The fuse does not cut off at that
> point, but allows even more current than that.

FWIW, my Samsung (not SanDisk) Fit Plus USB 64GB stick draws 40mA when
idle and 50mA when reading. (I didn't try writing, because I do not want
to overwrite/add_to the content.)

This is also a mini-stick, but has a metal housing and a metal barrel.

On Thu, 12 Oct 2023 12:04:27 +1100, Peter Jason <pj@jostle.com> wrote:

>A Sandisk 64GB mini. "Ultra Fit"
>
>All thumb drives heat up when operating, but why to they heat up and
>remain so when plugged in and idle?
Thanks to all. I'll try other brands, maybe the Samsung. The
small-size thumb drives are better because they do not snag things.

On 2023-10-12 23:49, Peter Jason wrote:
> On Thu, 12 Oct 2023 12:04:27 +1100, Peter Jason <pj@jostle.com> wrote:
>
>> A Sandisk 64GB mini. "Ultra Fit"
>>
>> All thumb drives heat up when operating, but why to they heat up and
>> remain so when plugged in and idle?
> Thanks to all. I'll try other brands, maybe the Samsung. The
> small-size thumb drives are better because they do not snag things.

The smaller a thumb drive is, the warmer it gets (if the other factors
stay the same). Stands to reason, the same energy concentrates in a
smaller size.

--
Cheers,
Carlos E.R.

On 10/13/2023 6:34 AM, Carlos E. R. wrote:
> On 2023-10-12 23:49, Peter Jason wrote:
>> On Thu, 12 Oct 2023 12:04:27 +1100, Peter Jason <pj@jostle.com> wrote:
>>
>>> A Sandisk 64GB mini. "Ultra Fit"
>>>
>>> All thumb drives heat up when operating, but why to they heat up and
>>> remain so when plugged in and idle?
>> Thanks to all.   I'll try other brands, maybe the Samsung.   The
>> small-size thumb drives are better because they do not snag things.
>
> The smaller a thumb drive is, the warmer it gets (if the other factors stay the same). Stands to reason, the same energy concentrates in a smaller size.

4.5 watts is a beastly power consumption for a small device
that is wrapped in plastic. Even if the USB stick was three
inches long, you'd still have a hot spot and a burning smell.

That's why it needs to be measured.

I definitely have USB3 flash sticks here, that the connector
gets warm. But that's not 4.5W, that might be 0.5W perhaps.

Paul

On 2023-10-13 16:21, Paul wrote:
> On 10/13/2023 6:34 AM, Carlos E. R. wrote:
>> On 2023-10-12 23:49, Peter Jason wrote:
>>> On Thu, 12 Oct 2023 12:04:27 +1100, Peter Jason <pj@jostle.com> wrote:
>>>
>>>> A Sandisk 64GB mini. "Ultra Fit"
>>>>
>>>> All thumb drives heat up when operating, but why to they heat up and
>>>> remain so when plugged in and idle?
>>> Thanks to all.   I'll try other brands, maybe the Samsung.   The
>>> small-size thumb drives are better because they do not snag things.
>>
>> The smaller a thumb drive is, the warmer it gets (if the other factors stay the same). Stands to reason, the same energy concentrates in a smaller size.
>
> 4.5 watts is a beastly power consumption for a small device
> that is wrapped in plastic. Even if the USB stick was three
> inches long, you'd still have a hot spot and a burning smell.
>
> That's why it needs to be measured.
>
> I definitely have USB3 flash sticks here, that the connector
> gets warm. But that's not 4.5W, that might be 0.5W perhaps.

Not at my current location, but in a few weeks I can rig up a usb-usb
cable and insert a multimeter. But I don't have any thumb drive that
heats too much.

--
Cheers,
Carlos E.R.

On 10/13/2023 5:05 PM, Carlos E. R. wrote:
> On 2023-10-13 16:21, Paul wrote:
>> On 10/13/2023 6:34 AM, Carlos E. R. wrote:
>>> On 2023-10-12 23:49, Peter Jason wrote:
>>>> On Thu, 12 Oct 2023 12:04:27 +1100, Peter Jason <pj@jostle.com> wrote:
>>>>
>>>>> A Sandisk 64GB mini. "Ultra Fit"
>>>>>
>>>>> All thumb drives heat up when operating, but why to they heat up and
>>>>> remain so when plugged in and idle?
>>>> Thanks to all.   I'll try other brands, maybe the Samsung.   The
>>>> small-size thumb drives are better because they do not snag things.
>>>
>>> The smaller a thumb drive is, the warmer it gets (if the other factors stay the same). Stands to reason, the same energy concentrates in a smaller size.
>>
>> 4.5 watts is a beastly power consumption for a small device
>> that is wrapped in plastic. Even if the USB stick was three
>> inches long, you'd still have a hot spot and a burning smell.
>>
>> That's why it needs to be measured.
>>
>> I definitely have USB3 flash sticks here, that the connector
>> gets warm. But that's not 4.5W, that might be 0.5W perhaps.
>
> Not at my current location, but in a few weeks I can rig up a usb-usb cable and insert a multimeter. But I don't have any thumb drive that heats too much.
>

It's easier, to find a version similar to one of these. The prices vary.
My computer store doesn't have any of this sort of gadget.

https://www.amazon.com/AVHzY-Digital-Multimeter-Detector-26-0000V/dp/B073R7YRM9/ref=sr_1_3?keywords=usb%2Bct3&sr=8-3&th=1

This one isn't as fancy. It doesn't have USB-C connectors and it is not
likely intended for USB-PD situations. For the USB stick measurement, this
would be fine.

https://www.adafruit.com/product/2690

"3.7 to 13VDC input voltage (although most USB devices tend to hover around 4.75 to 5.25)
Up to 3A of current"

"There's a 0.025 ohm resistor in line with the power pin"

The reason they tell you that, is so you can understand
"how much disruption to bus power" results from using the device.
3 amps flowing through 0.025 ohms is 75mV of voltage drop.
Therefore, at the limit of its useful range, that's the most
disruption it would cause. Normal USB3 currents are lower.

However, this statement in the advert (full disclosure), tells you
why you would not buy it. No good for USB3 realistic testing.

"USB 1.x and 2.x - all data speeds. Does not have USB v3 pins
so USB v3 connections will automatically downgrade to v2"

If power consumption was related to USB3 protocol actions, you
would not be doing a proper evaluation of the behavior. If they put
a USB3 connector on the board, they would likely have needed multi layer
PCB for the thing, and stripline or microstrip transmission. Perhaps
a USB2 version could use a two layer board.

Paul

On 2023-10-13 23:36, Paul wrote:
> On 10/13/2023 5:05 PM, Carlos E. R. wrote:
>> On 2023-10-13 16:21, Paul wrote:
>>> On 10/13/2023 6:34 AM, Carlos E. R. wrote:
>>>> On 2023-10-12 23:49, Peter Jason wrote:
>>>>> On Thu, 12 Oct 2023 12:04:27 +1100, Peter Jason <pj@jostle.com> wrote:
>>>>>
>>>>>> A Sandisk 64GB mini. "Ultra Fit"
>>>>>>
>>>>>> All thumb drives heat up when operating, but why to they heat up and
>>>>>> remain so when plugged in and idle?
>>>>> Thanks to all.   I'll try other brands, maybe the Samsung.   The
>>>>> small-size thumb drives are better because they do not snag things.
>>>>
>>>> The smaller a thumb drive is, the warmer it gets (if the other factors stay the same). Stands to reason, the same energy concentrates in a smaller size.
>>>
>>> 4.5 watts is a beastly power consumption for a small device
>>> that is wrapped in plastic. Even if the USB stick was three
>>> inches long, you'd still have a hot spot and a burning smell.
>>>
>>> That's why it needs to be measured.
>>>
>>> I definitely have USB3 flash sticks here, that the connector
>>> gets warm. But that's not 4.5W, that might be 0.5W perhaps.
>>
>> Not at my current location, but in a few weeks I can rig up a usb-usb cable and insert a multimeter. But I don't have any thumb drive that heats too much.
>>
>
> It's easier, to find a version similar to one of these. The prices vary.
> My computer store doesn't have any of this sort of gadget.
>
> https://www.amazon.com/AVHzY-Digital-Multimeter-Detector-26-0000V/dp/B073R7YRM9/ref=sr_1_3?keywords=usb%2Bct3&sr=8-3&th=1
>
> This one isn't as fancy. It doesn't have USB-C connectors and it is not
> likely intended for USB-PD situations. For the USB stick measurement, this
> would be fine.
>
> https://www.adafruit.com/product/2690
>
> "3.7 to 13VDC input voltage (although most USB devices tend to hover around 4.75 to 5.25)
> Up to 3A of current"
>
> "There's a 0.025 ohm resistor in line with the power pin"

Cute.

>
> The reason they tell you that, is so you can understand
> "how much disruption to bus power" results from using the device.
> 3 amps flowing through 0.025 ohms is 75mV of voltage drop.
> Therefore, at the limit of its useful range, that's the most
> disruption it would cause. Normal USB3 currents are lower.
>
> However, this statement in the advert (full disclosure), tells you
> why you would not buy it. No good for USB3 realistic testing.
>
> "USB 1.x and 2.x - all data speeds. Does not have USB v3 pins
> so USB v3 connections will automatically downgrade to v2"

Better use a gadget that uses a plain USB connector and socket, same as
my computer. 4 wires.

>
> If power consumption was related to USB3 protocol actions, you
> would not be doing a proper evaluation of the behavior. If they put
> a USB3 connector on the board, they would likely have needed multi layer
> PCB for the thing, and stripline or microstrip transmission. Perhaps
> a USB2 version could use a two layer board.
>
> Paul

--
Cheers,
Carlos E.R.