Tag: usb
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USB Inrush Testing
The USB spec has limits on the ‘inrush current’, which is designed to prevent you from having 2000uF of capacitance that must be suddenly charged when your board is plugged into the USB port. The limit works out to around 10uF of capacitance . Your board might have much much more – so you’ll have…
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Split Ground Plane: Example of failing high-speed signals
I’ve got a SASEBO-W board, which has a FPGA & a FT2232H for high-speed USB comms. I was seeing errors on the high-speed USB device, and couldn’t figure out why: Power Split The SASEBO-W is a multi-purpose board including a Xilinx LX150 Spartan 6 FPGA and a FTDI FT2232H USB interface. One use of the…