T-2081 QORIQ PowerSupply Design

[tkchaitanya]

Hi all,

I'm trying to design power supply for T2081 processor and i got the t1040/t2081 rdb reference design.

But i want to know whether power supply sequencing is needed or not?(as per app note attached not required but not sure)

if not then i would like to remove the associated cktry multiphase controller and the MOSFET part of the power supply section in schematics.

Please help.Thanks in advance.

[tkchaitanya]

Hi,

Thank you as per your suggestion I've removed power sequencing sequencing mechanism and all USB power supply pins are gnded.

So can you please confirm if it is fine.

[ufedor]

Required power sequencing for the T2081 is described in the data sheet T2081 QorIQ Integrated Multicore Communications Processor, Rev. 1, 3.2 Power sequencing.

The data sheet is available at:

https://www.nxp.com/webapp/Download?colCode=T2081&location=null&fpsp=1&WT_TYPE=Data%20Sheets&WT_VEND...

[tkchaitanya]

Hi ufedor,

Thank you for the quick response, I've following queries based on your answer:

1. The power sequencing suggested by datasheet is for USB only but we're not going to use USB in our design so should I skip the power sequencing mechanism

2. Since I'm not going using USB so what to do with related USB power supply pins (USB_SVDDx,USB_HVDDx,USB_OVDDx)? should be floated or  grounded. Please suggest.

Thanks in advance.

[ufedor]

If USB is not used the USB_HVDD, USB_OVDD and USB_SVDD have to be tied to ground.

Reference:

http://www.nxp.com/files/32bit/doc/app_note/AN4804.pdf

Table 3. Power and ground pin termination checklist

[tkchaitanya]

Hi ufedor,

So making usb voltages grounding means can i skip power sequencing b'coz my basic quest is to decide whether to implement power sequencing or not. Please suggest

[ufedor]

No power sequencing is needed if USB is unused.