i.MX7's USB_OTG1_VBUS threshold and some questions.

[HOTA]

Hi,
I have a question regarding the i.MX7 USB_OTG1_VBUS terminal. Could you please assist?

1. What is the threshold voltage for i.MX7's USB_OTG1_VBUS?
2. What is the design default voltage for OTGTUNE0 (VBUS Valid Threshold Adjustment) set at 100b?
3. Is it okay to apply voltage to VBUS when the i.MX is not powered on?
4. If always in device mode (including serial download mode), can VDD_USB_OTG1_3P3_IN and USB_OTG1_VBUS be directly connected and used?
5. Us USB_OTG2_VBUS the same in terms of these characteristics?

The reason for these questions is that I could not find voltage information in the spec sheet beyond the absolute maximum rating of 5.25V. Also, from the EVA circuit diagram, I understood it to be kept low when the i.MX7 is not powered on. I would like to confirm whether it's okay to directly connect from the USB terminal or use a resistor divider.

[HOTA · Accepted solution]

Hi Ritesh M Patel,

Thank you for your response. After scrutinizing the information provided, I understand that the circuit diagram based on the EVA is rational. I will create a circuit diagram following the EVA.

Thanks,

HOTA

[riteshmpatel]

Hi @HOTA,

I hope you are doing well.

Please see the response to your questions below:

• What is the threshold voltage for i.MX7's USB_OTG1_VBUS?

[NXP]: It follows the USB 2.0 standard. It is 5.0V +/- 5% i.e. 4.75V.

• What is the design default voltage for OTGTUNE0 (VBUS Valid Threshold Adjustment) set at 100b?

[NXP]: It is as per the USB 2.0 Standard (5.0V +/- 5%) i.e. 4.75V.

• Is it okay to apply voltage to VBUS when the i.MX is not powered on?

[NXP]: It is not recommended to apply voltage on VBUS when the i.MX is not powered.

• If always in device mode (including serial download mode), can VDD_USB_OTG1_3P3_IN and USB_OTG1_VBUS be directly connected and used?

[NXP]: The voltage level of VDD_USB_OTG1_3P3_IN and USB_OTG1_VBUS are different. So, they cannot be directly connected.

• Us USB_OTG2_VBUS the same in terms of these characteristics?

[NXP]: Yes.

Thanks & Regards,
Ritesh M Patel