The HX3PD's datasheet says (under "DC Electrical Characteristics" section) that "VBUS for upstream port" voltage must not exceed 5.25V. At the same time VBUS itself can clearly be up to 20V nom. What exactly is VBUS pin (M7 in BGA pacakage) intended for? The pin description section hints that it is a digital input. So I assume that is is kind of VBUS present/not present. Can I interface it to the actual VBUS with a huge resistor hoping that any excessive voltage will be clamped at the pin? See the screenshot attached. Thank you.
Hello,
Yes, the VBUS pin is used to detect VBUS presence on the upstream port and enable the hub controller. To monitor the actual VBUS on the upstream port, VBUS_MON_P0 pin is used.
You could connect VBUS directly to the pin using a resistive divider to ensure that the value doesnt exceed 5.25V but you would have to adjust that based on what VBUS is selected as per the PD negotiation. Hence, we recommend connecting the VBUS_C_CTRL_P0 to the VBUS pin as shown in our App Note on HX3PD hardware guidelines.
Best Regards,
Sananya
Hello,
Yes, the VBUS pin is used to detect VBUS presence on the upstream port and enable the hub controller. To monitor the actual VBUS on the upstream port, VBUS_MON_P0 pin is used.
You could connect VBUS directly to the pin using a resistive divider to ensure that the value doesnt exceed 5.25V but you would have to adjust that based on what VBUS is selected as per the PD negotiation. Hence, we recommend connecting the VBUS_C_CTRL_P0 to the VBUS pin as shown in our App Note on HX3PD hardware guidelines.
Best Regards,
Sananya
