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Hi,
Not sure if its the best forum for this question, but I could not find any better.
A while ago I designed a USB Isolator based on ISOUSB111 chip. As the datasheet tells its 1.5/12 Mbit USB1.1 or full speed chip, so high data rates should not be expected... I designed it with an extra power margin, total of 2A @ 5V. And it works, I can get my USB flash drive recognized, transfer data between it and PC, it also works in transferring data between PC and my phone.
However, I designed that isolator primarily to use with USB electronics measurement instruments (in my case Liber VNA vector analyzer and SA44B spectrum analyzer.) I am aware that such instruments feed quite a bit of data to the PC to process, on the other hand, USB is advertised to be backwards compatible. As you can already guess, neither the VNA or spectrum analyzer dont work (dont even get recognized as USB devices) when connected via isolator. Both instruments are tested and used before, connected directly to PC, they work with no problem. Datasheets of both instruments are not very rich in documentation about USB standards. (The SA44B has USB-B connector on its own, so it has to be USB HS (2.0), the VNA has a type-C connector, not sure about real USB 3.0 capability, maybe its also USB HS, but type C is there only for the convenience.) I feel like there is not point in pasting my Altium schematics and layout files here, as problem is not in the hardware... I expect both devices to run significantly slower, but still function as intended, but there is no response at all. Is there anything I am missing about the USB FS-HS compatibility? An additional observations?
Thanks.
Not sure if its the best forum for this question, but I could not find any better.
A while ago I designed a USB Isolator based on ISOUSB111 chip. As the datasheet tells its 1.5/12 Mbit USB1.1 or full speed chip, so high data rates should not be expected... I designed it with an extra power margin, total of 2A @ 5V. And it works, I can get my USB flash drive recognized, transfer data between it and PC, it also works in transferring data between PC and my phone.
However, I designed that isolator primarily to use with USB electronics measurement instruments (in my case Liber VNA vector analyzer and SA44B spectrum analyzer.) I am aware that such instruments feed quite a bit of data to the PC to process, on the other hand, USB is advertised to be backwards compatible. As you can already guess, neither the VNA or spectrum analyzer dont work (dont even get recognized as USB devices) when connected via isolator. Both instruments are tested and used before, connected directly to PC, they work with no problem. Datasheets of both instruments are not very rich in documentation about USB standards. (The SA44B has USB-B connector on its own, so it has to be USB HS (2.0), the VNA has a type-C connector, not sure about real USB 3.0 capability, maybe its also USB HS, but type C is there only for the convenience.) I feel like there is not point in pasting my Altium schematics and layout files here, as problem is not in the hardware... I expect both devices to run significantly slower, but still function as intended, but there is no response at all. Is there anything I am missing about the USB FS-HS compatibility? An additional observations?
Thanks.
