Electronics > Projects, Designs, and Technical Stuff
USB Superspeed connector question
moffy:
I am designing an FT600Q to USB Superspeed interface at present, and am getting a little confused about the USB connector and power negotiation/detection.
The FT600Q datasheet: https://ftdichip.com/Support/Documents/DataSheets/ICs/DS_FT600Q-FT601Q%20IC%20Datasheet.pdf
gives BUS powered example circuits but says this is only valid for the superspeed type B or micro B connectors, but I have opted for the more common Type A superspeed connector which appears to have all the requisite signals of the example.
The connector is: https://www.belfuse.com/resources/drawings/stewartconnector/dr-stw-ss-52000-001.pdf
The circuit at present is attached, please excuse the lack of decoupling capacitors, they will be added. My question is, should this work? or am I missing something? If someone could also clarify how for a USB_A to USB_C host the detection and power negotiation works that would be appreciated. The FT600Q also has a resistor R8 in the attached schematic that has something to do with power negotiation but I'm not sure what. Thanks in advance.
ataradov:
It will work on a logical level, but Type A connector can only be a power source. And standard Type-A to Type-A cables will not have VBUS connected at all. Although most random Chinese cables have it and it is dangerous and not compliant.
I personally would stay away from Type A for this application.
moffy:
--- Quote from: ataradov on January 15, 2025, 10:57:12 pm ---It will work on a logical level, but Type A connector can only be a power source. And standard Type-A to Type-A cables will not have VBUS connected at all. Although most random Chinese cables have it and it is dangerous and not compliant.
I personally would stay away from Type A for this application.
--- End quote ---
What would be your recommendation? Type B or C? I originally started with a Type C, but in one example circuit I found they used a mux to select between the two sets of superspeed inputs and outputs, whereas I was blithely happy just to parallel them. Is it possible just to parallel connect the dual sets of superspeed signals, and would there be any other issues with using Type C for this application?
ataradov:
I would go with Type-C, but you have to tolerate the annoyance or routing and having to add the mux. Otherwise Type-B is the only real option.
It is not possible to just parallel them. It will not work at SS speeds. The way to know this for sure is to observe that even the cheapest junk from Aliexpress does not do it. And they would cut any corners they can.
moffy:
--- Quote from: ataradov on January 15, 2025, 11:13:16 pm ---I would go with Type-C, but you have to tolerate the annoyance or routing and having to add the mux. Otherwise Type-B is the only real option.
It is not possible to just parallel them. It will not work at SS speeds. The way to know this for sure is to observe that even the cheapest junk from Aliexpress does not do it. And they would cut any corners they can.
--- End quote ---
Type C it is then with a mux added, thanks.
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