TUSB9261: Question about TUSB9261 PIN 4 GRST#

Hi Chongyu,

Chongyu Long said:

1. Can I omit this pin detection with the firmware?

GRSTz is needed in order to properly ensure the device meets the power-up timing requirements, which is a minimum of 2ms, or until Vdd is at acceptable levels.

Chongyu Long said:

2. If this pin cannot be omitted, how should we design the delay circuit?

If this pin is being controlled externally, such as by an MCU or power regulator, it can be controlled to be asserted for a certain amount of time on reset before coming online. If not, a passive RC circuit can be created using the correct values of capacitors needed to have the pin asserted until the device is powered into the recommended range.

Please let me know if you have any other questions.

Thanks,

Ryan