Other Parts Discussed in Thread: TPD6E05U06, , TPD4E05U06
Hello
I have been studying your datasheets, reference designs, and development boards and I have not seen any mention of any data line termination. Am I safe to assume that if I match the impedance of my traces to 45 ohm single ended or 90 ohm differential no termination is required, other than the AC coupling capacitor on the TX line? I.e. that it is embedded on the chip where appropriate.
I also wanted to ask what your recommendation on ESD protection devices is. As most of them have footprints significantly larger than my traces there will be a significant impedance mismatch which will cause reflections to occur. Do you have any suggestions how to handle this? I have found that using your TPD6E05U06 the reflection coefficient can be kept below 0.2. The same reflection issue will occur on the hub footprint but can be kept at the same level.
I also wanted to ask about the PWRCTLX pins. They all incorporate a Pull Down resistor and as I am using the GANGED mode of the device I understand that I can leave 3 of them unconnected, leaving no battery charging support on those three ports, and use the last one still with a pull down to enable or disable the current for all the downstream ports. Am I correct in my understanding of the PWRCTLX pins?
Lastly I wanted to ask about the EEPROM. I am planning to allow a microcontroller to share the I2C bus with the EEPROM and the hub in order to reprogram the EEPROM easily if needed. Does the hub have an I2C address? As far as I can tell it only requires the EEPROM to have a specific address but doesn't state its own, presumably because it should never be addressed. Am I missing something from the datasheet that would not allow me to configure the device like so?
I hope that these questions are clear enough, if not please let me know and I will clarify them further. I am currently in the process of making a schematic and selecting components for a new design using the TUSB8041.
