USB 3.0  to SATA and back - Page 1
Forum section: electronics / beginners

author: AE7OO
author_rank: Regular Contributor
timestamp: April 24, 2019, 04:50:02 am
content: Hello,I'm trying to setup a completely isolated system. Everywhere I read(outside of single ap note from Analog) various sources say that it is not possible to isolate USB 2.0 HS or any form of USB 3.0.But I have seen at least 2 different USB 3.0 to SATA converters out in the wild. And last time I checked, SATA used LVDS as its signaling layer. And there are 3 chips from Analog alone that will isolate LVDS at 600Mbps.So why would the following not work:Via Tech VL713 -- USB 3 to SATAAnalog Devices ADN4651 -- LVDS isolator with a max data rate of 600MbpsUSB 3.0 cable --> USB 3.0 socket -> usb 3.0 --> VIA VL713--> LVDS --> AD4651 --> LVDS -->VIA VL713 --> usb 3.0 --> usb3.0 socket --> usb 3.0 cableYes, it is a little round about and limited to 600Mbps, which is still MUCH faster than the current USB limit of 12Mbps.With some attention to detail and not doing anything stupid, I don't see any problems.VL710/3/6 $3 - $5 -- AliExpress --https://datasheet.lcsc.com/szlcsc/VIA-Tech-VL716-Q4_C69727.pdfAD4651 $10 -- Mouser --https://www.analog.com/media/en/technical-documentation/data-sheets/ADN4650-4651-4652.pdfThe board would cost around $40 to make, I think.Should this work, or am I digging a whole I can't get out of??

author: DC1MC
author_rank: Super Contributor
timestamp: April 24, 2019, 05:01:09 am
content: Get two of these 4KV isolated babies and mount them head to head, problem solved:https://www.coolgear.com/product/gigabit-ethernet-usb31-gen1-adapter-4kv-isolation-mounting-kitAs software use the nice and delicate USB over Ethernet drivers for Windozer:http://www.usb-over-ethernet.com/Linux has this:http://usbip.sourceforge.net/It will be like 169 times easier than fidgeting with SATA drivers and 2096 times more portable and supported..Cheers,DC1MCIt will be like

author: ogden
author_rank: Super Contributor
timestamp: April 24, 2019, 05:08:12 am
content: Quote from: AE7OO on April 24, 2019, 04:50:02 amNo. USB to SATA converters are not just physical interface converters. You can't connect such back to back and expect that signals will go through. They won't.QuoteHave you tried tosearch for actual USB 2.0 HS isolator product?

author: magic
author_rank: Super Contributor
timestamp: April 24, 2019, 07:03:00 am
content: In addition to what everyone said so far:Quote from: AE7OO on April 24, 2019, 04:50:02 amAhem.

author: David Hess
author_rank: Super Contributor
timestamp: April 24, 2019, 01:39:08 pm
content: USB to fiber converters exist for extended range applications which could be used for galvanic isolation.

author: AE7OO
author_rank: Regular Contributor
timestamp: April 24, 2019, 04:56:06 pm
content: Yes, I had searched for USB 2.0 HS isolators. Nothing within reason. The majority of the products showing "High Speed USB Isolation" are really FS devices.Yes, it was me being lazy for not doing more research on the USB 3 physical layer. If I had, I would never even thought of using those USB/SATA converters when there is NO reason, when USB 3 is a type of LVDS...I think I'm going to sample a couple of the AD LVDS isolators and see what I can do.Need to order about 20 sma board edge connectors and make 2 USB 3 breakout boards and the eval board for the AD ADN4645https://www.analog.com/en/products/adn4654.html.Not that hard, use 4 layers and strip line construction.I'll try not to be so lazy next time.

author: ogden
author_rank: Super Contributor
timestamp: April 24, 2019, 05:09:19 pm
content: Quote from: AE7OO on April 24, 2019, 04:56:06 pmInthis threadsome mentioned isolators seems like very reasonable:https://hifimediy.com/Accessories/high-speed-usb-isolator-480MbpsUSB 3.0, 10m optical cable isolator :https://www.corning.com/optical-cables-by-corning/worldwide/en/products/usb-optical-cables.html

author: David Hess
author_rank: Super Contributor
timestamp: April 24, 2019, 07:52:45 pm
content: Quote from: ogden on April 24, 2019, 05:09:19 pmI do not think those Corning cables are actually galvanically isolated. They apparently still keep the power connections which makes sense because the device end cannot rely on getting power from an "input". Both ends need to be self powered.This is the type of device I was thinking of:https://www.amazon.com/Transwan-Extender-Transmiter-Receiver-Supports/dp/B0798HHNJV/There are similar but cheaper fiber converters for USB 2.The major problem with USB is that the USB 2 electrical interface is half duplex so a converter needs to also operate as a bridge.USB 2 over Gigabit Ethernet is also possible but USB 3 would make no sense so the above device uses fiber transceivers.

author: ogden
author_rank: Super Contributor
timestamp: April 24, 2019, 08:01:26 pm
content: Quote from: David Hess on April 24, 2019, 07:52:45 pmYes, you are right. Connectiondiagram (pdf)clearly shows copper 28AWG for power running along the fiber. I rushed to believe what was said in mentioned thread w/o looking into product docs. Apologies.