USB Flash Drive w/ Crystal Oscillator

[NickMMM]

Hi,

I am looking to buy (or have custom made) a USB Flash Drive<12 units, at first> at any capacity, preferably more than 512MB, that has a crystal oscillator. This would be versus a silicon oscillator. An even better benefit would be an oscillator with low jitter, I assume this would be a 'higher quality' oscillator. Any and all help would be greatly appreciated.

Thanks,

Nick

[Geek-9pm]

Well, you could make your own. What frequency you need?
This forum has a policy about strange hardware and software used to victimize other people. What you describe, a USB device with an non-board Oscillator , is often used by spies to taker data  form a Vitim's computer.
Photo:

Would you like to explain what you have in mind?

[NickMMM]

You may have just murdered the english language....that being said, if I was looking to steal or victimize anyone, I could do that. That's easy & practical. What I need is not a separate oscillator. I just need a flash drive with a crystal oscillator versus a silicon one that seem to frequent almost every single new flash drive.

[Geek-9pm]

My problem is spelling.  And typing. And I  can't find my dictation software.

Crystal oscillators on a USB are sold as 'clandestine ' devices.

Again, what frequency do you need? And what kind of oscillator does the common Flash drive normally have? And why would it make a difference? What measurements have your made on a flash chip that leads you to think thee is a stability issue? Are you waiting to build a time base device? 

Pardon me, but In just don't understand. If you want precision time, the PC already does that for you. Do you need a portable frequency standard? 

What may seem to be instability in a flesh  drive is not the clock rate. It has to do with the quality and speed of the device and the thermal limits.  Writing tends to heat up a flash device and is slower than a read. It is not a change in clock, rather the write cycles are longer. By design. Using a crystal would not change that.
So, what do you want to do?

This link is for users who have some engineering experience.
http://www.ftdichip.com/Support/Documents/AppNotes/AN_100_Using_The_FT232_245R_With_External_Osc%28FT_000067%29.pdf

[NickMMM]

What I am looking to do is very unconventional, it's a counter-intuitive process we are using them for. In a conventional approach, I don't think you would see a difference between silicon or crystal. With this it matters. Quite the rare item now-a-days, so it seems... traditional flash drives have an oscillator that clocks at 12.000 Mhz

[Geek-9pm]

OK. Got the idea. (The OP is talking about a 12 MHz quartz crystal. )

The free running oscillators are used in many devices where high precision is not needed. The accuracy is usually inside of 2%, wheres a  crystal can stay inside of a 0.005 % range and are often used for clocks and frequency counters as will as RF transmitters. I suppose you don't want a RF transmitter.
You may be able to order it custom made. but that is a rather rare item. Look over the data sheets for the flash chips and see if there is ab option of locking the internal oscillator to a crystal. Most crystals, in my own experiments, will lock a free-running circuit, even when lightly coupled through a small capacitor. Look for a  circuit  where the internal  oscillator has an external pin for a frequency-setting capacitor.

This page claims many drives have a crystal.
http://www.bestelectronicarticles.com/computers/usb/how-to-repair-usb-flash-drive.html
As does this one
http://www.durofy.com/inside-the-usb-pen-drive/
Is this of any help?

[NickMMM]

I'm actually looking for a link to buy one.

[Geek-9pm]

I'm actually looking for a link to buy one.

Apparently some come with crystal. Some maybe you have to call the vendor to find out what they want to sell you.
BTW a quartz crystal can be fragile. Bang it hard and it stops working. That might explain why some drives fail after awhile.

http://www.flashbay.com/support/faq/flash-drives-review

[camerongray]

I fail to see the actual point of this thread.  What would the type of crystal used in the drive have to do with anything?

[Geek-9pm]

I fail to see the actual point of this thread.  What would the type of crystal used in the drive have to do with anything?

I asked the OP  that already. He was vague in his reply.

FYI very cheap USB devices do not use a quartz  crystal. This can cause tinning errors which could  make the device less reliable in some applications. But the OP never made this clear. So I have to guess.

[Lisa_maree]

The trouble you have is it's optional to use an oscillator or crystal in a pen drive and most manufactures need to keep costs down so op not to use either and stick with the silicon circuit instead.
I suggest you purchase several older designed pen drives , if you can find old stock from 5 years or older you will have a better chance of finding what you want.
The only pen drive I could find here with an oscillator was a legend 512mb thats 6 years old.   
We also have all the current pen drive PCB's  and none have the option of a crystal or oscillator.
So to get what you are looking for you would need  to have a run made using old PCB's and for 10 that would be at least $100.00 each.


 

[NickMMM]

Lisa_maree,

a run of 10 or 12 would be perfect, is this something you can do?

Thanks!

[NickMMM]

or am I able to buy 10-12 of those legend flash drives?

[Geek-9pm]

The trouble you have is it's optional to use an oscillator or crystal in a pen drive and most manufactures need to keep costs down so op not to use either and stick .... you would need  to have a run made using old PCB's and for 10 that would be at least $100.00 each.

Lisa_maree, are you making wild guess? I think I could find about 50 of them for about $12 each. They are not so rare. Yet.

[DaveLembke]

I cracked open a Trend Micro 4Gb stick the one day to touch up on a cold solder joint and it still had the 12mhz crystal in it. Look for one in clear plastic to see what you are getting the one I have is in clear red plastic.

This Reader has the 12mhz crystal as you can see thru the clear plastic and you can turn it into a USB Flash Drive... other actual flash drives exist with clear plastic to see the internals without gambling on if crystal or not. http://www.ebay.com/itm/USB-SD-Clear-Card-Reader-Writes-Reads-SD-SDHC-Turn-a-SD-Card-into-a-flash-drive-/221308911237?pt=AU_Digital_Memory_Card_Readers_Adaptors&hash=item338709fe85#ht_792wt_1133


This one here may also have a crystal in it. I'd contact the seller to have them take a picture for you with the thumb drive folded out to see thru the clear plastic to the PCB and verify that a crystal is present. http://www.ebay.com/itm/8GB-Swivel-Metal-USB2-0-Flash-Drive-Memory-Stick-Thumb-Ricco-01-001-CLEAR-PURPLE-/130844029782?pt=UK_Computing_FlashDrives_SM&hash=item1e76e97356#ht_2847wt_896