USB Isolator recommendation


I use a USB isolator to protect my laptop when doing HV prototypes etc

I using this one:

But, sometimes it wont feed the USB through, so equipment attached on the hot side wont enumerate

I need something I can trust

Do you have a recommendation?



I’ve seen optical USB cables that exist primarily for long-haul reasons - they are not galvanically isolated as they come out of the box – but I suspect they could be modified with a DC:DC isolated module.

… and then I just looked on Amazon to see what’s available these days and see a bunch of low-cost (non-optical) isolated USB offerings – many quite inexpensive, though limited to USB full speed (12 Mbps).

Saleae recommends AllDAQ USB isolators.

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Do you need high-speed? That is the major complexity if so… I’ve used the Intona unit (, though that AllDAQ one looks a like nicer TBH so I’d probably go with that instead!

If you only need full-speed options are pretty open. I’ve used the Adafruit isolator ( successfully, no major usage just a few times here and there though, so can’t comment about long-term reliability.

I just bought the AllDAQ through Saelig.

Timely post. I spent too long just this morning fighting a noise issue. Forgot that my FPGA JTAG programmer was still connected which created a ground loop with the scope… It’s past time. Will let you know how it goes after I use it for a few days.

They look great, thanks. Just ordered a set :slight_smile:

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For a cheap and cheerful option I’ve just used this Olimex one for basic USB2 and it’s always worked well.

Nice, a lot cheaper :wink:

Are there any isolators like this that you can tell are being used? The one’s I’ve seen are completely transparent on the bus, and I’d like to be able to do something like query the USB tree and see that the isolator is in use / the user didn’t just plug straight into the end device.

My current (bad) plan is to put a hub just after the isolator and wrap the two together as one unit. I just need something foolproof, I don’t need it to be malice-proof.

From memory I think the Olimex one is visible on the bus, I think it shows up as a hub. I have one here somewhere…

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