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Should the two ground terminals (pins 3 & 8) on the ESD7004 (TVS ESD Protection Diode for High Speed Data Line) be connected together with a trace under the part on the PCB, or should the USB ground lead (pin 5) from the USB connector pass through the part before connecting to the PCB ground? If so, what is the maximum operating current that can pass through the device (e.g., for charge return currents on VBUS)?
It is not recommended to have a trace underneath the part connecting the two GND pads on the ESD7004 (ESD Protection Diode for High Speed Data Line) as these two pins are internally connected. Because of this, only one GND pin is theoretically required, however the typical connection is to have one 5mil wide, ~40mil long trace to a GND via that leads to the internal GND plane on each GND pin. If you need to reduce the number of GND vias close to the high speed data lines, then you can use one of these traces to connect to the GND plane.
Also, it is not recommended to run a trace directly from the USB connector as this will create a large inductive path to the GND plane. I would suggest having the mounting hole, for the connector GND lead, connect directly to the GND plane.
Answered by: ON Semiconductor
2013-05-21 09:41:11.3