Intona User Forum

Hi Daniel

Some questions:

1. For the USB 2.0 5kV isolator (7055-B) - is the "data" isolated optically?

2. Also, since Intona does not present as a USB hub to connected PC/Mac, then does this mean it does NOT 'regenerate' the USB signal like a USB hub does?
Or it does regenerate the USB signal (signal integrity), despite not being a USB hub?

3. Is the AUX power input of 7055-B electrically galvanically isolated also? SMPS's (even good ones) typically output 'leakage currents'. Curious if AUX input will isolate from these.

Thanks!

1. It is "dark" isolated. Same result as optical but with another technology. This is done using high speed CMOS isolators by Silicon Labs (formerly -- now sold to Skyworks Solutions). There is no way for direct optical isolation of USB 2.0 today. Using VCSEL (laser) technology like on the USB 3.0 wires (7055-D) would be possible in theory but 2.0 is way to slow (like DC) for these little puppies.

2. Oh yes, the isolator regenerates definitely. Unlike a hub, it does this on the physical layer and not on the protocol layer. This makes it transparent to host and device.

3. The AUX is considered galvanically isolated to the HOST. So, it's definitely galanically *connected* to the DEVICE. The reason of this is that the internal 5kV-Isolation is only capable of transmitting 500 Milliamps. There are certain reasons, why this cannot be more (safety, dimensions). And the solution is connecting a linear power supply to the AUX, which can handle beyond 2000 Milliamps. Of course, every supply is galvanically isolated by design.
BTW, I wouldn't call it "leakage", I would rather call it "noise shortener". There is a capacitive connection between primary in secondary in every SMPS. But without capacitance (which shortens the SMPS-RF-Noise), it would be much worse. I know audiophiles don't want to beleive this. But it's a physical fact that can be proved with measurements. Pro tip: if you need a SMPS and want least leakage, go for a medical grade supply. High safety = low leakage.

Thanks Daniel !