T2080 - Power Sequence

[manikumar]

Hi,

For power sequence of T2080, referred to "3.2 Power sequencing" of datasheet (pg: 48). Please suggest on the following:

• Power sequence is not required apart from USB power, But for "USB_SVDD supply must ramp before or after the USB_HVDD and USB_OVDD supplies have ramped". Please confirm is it before or after
• PORESET_B signal should be asserted after all power supplies are settled. Please confirm. As per 3.7 Reset initialization section "PORESET_B must be driven asserted before the core and platform power supplies are powered up."

Regards,

Mani

[alexander_yakov]

"Before or after" means - not simultaneously. That is - USB_HVDD and USB_OVDD supplies should be either not applied, or already settled, when the USB_SVDD ramps up. Ramping up USB_HVDD and USB_OVDD simultaneously with USB_SVDD violate this requirement.

Section 3.2 states "PORESET_B input must be driven asserted and held during this step." meaning it must be asserted during power supplies ramp up.

[manikumar]

Hello Alexander,

Thanks for your reply.

In case if USB section is not used in T2080, can voltages for USB_HVDD,USB_OVDD and USB_SVDD be unused or even unused voltage to be applied. Please confirm.

Regards,

Mani