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about TUSB321 VBUS_DET PIN valid level

Part Number: TUSB321

1.VBUS_DET PIN is connected to VBUS with a 900K resistor, and there is a 95K pull-down resistor inside the TUSB321. After USB is inserted in actual measurement, VBUS_DET PIN is only 0.5V. I would like to know the VBUS_DET voltage threshold judged as USB insertion.

2.Can TUSB321 be powered by VBUS?  If VBUS is used for power supply, does it affect CC detection?  

  • Hello,

    1.VBUS detect threshold voltage is Vbus *  95k/( 95k+900K). So we can calculate the Vbus detect voltage is about 0.477V, so you tested 0.5V is normal.(Vbus=5V)

    VBUS detection voltage criteria is 300mv +-5%. above 350mv will be safe.

    2.  It is not recommended to use Vbus power VDD. It' better to use separate power supply.