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AWR2944P: Power sequence of 3.3v and 1.8v

Andy Yin
Genius 9300 points
Part Number: AWR2944P
Other Parts Discussed in Thread: AWR2944,

Tool/software:

Hi,

About 3.3v supply, need your help clarify below two questions, thanks.

1. In both AWR2944P and AWR2944 errata, ANA#44 suggest to supply 1.8v before 3.3v, if the design doesn't meet this requirement in case 3.3v is supplied from the pre-regulator, then 3.3v would possible come before 1.8v, any risk here, would it cause the radar device boot failure?

2. shown in below AWR2944P EVM figure, radar device 3.3v supply before 1.8v, while for the peripheral devices like Ethernet the 3.3v is supplied separately, such as supplied from pre-regulator, which would come before the radar device 3.3v and 1.8v, any risk here? 

3. any suggestion on the 3.3v for radar device and peripheral device, supply separately or from same power source?

Look forward to your reply, really thanks.

Andy

  • 0
    TI__Genius 16240 points

    Please find similar thread that was previously resolved. This should answer your question

    e2e.ti.com/.../awr2944-awr2944-power-sequence

  • 0
    Prodigy 20 points

    Hi Andy

    I think the answer provided by E. Shareef has addressed the third issue, but no one has responded to the first two problems yet.

         

  • 0 in reply to E. Shareef
    TI__Genius 9300 points

    Shareef,

    Already checked the thread, and read the checklist, understand the request is to ensure 3.3vIO is supplied after 1.2 and 1.8v. But it still doesn't answer my question directly. My question is if 3.3v come before 1.8v then any risk, would device not boot up?

    And the other question is if peripheral is supplied separately, and supplied before radar power, any risk?

    Thanks.

    Andy

  • 0 in reply to Andy Yin
    TI__Genius 16240 points

    Hello Andy,

    This depends on how the power is managed on the board. So there could be a risk with 3.3V coming up before the 1.2v and 1.8v.

    -E. Shareef

  • 0 in reply to E. Shareef
    TI__Genius 16240 points

    Hello Andy,

    Also from the Errata it seems to be clear that we have seen leakage into the 1.8V if 3.3V comes up first. Hence the suggestion to have 1.8V come up first.

    In this particular scenario, YES, it likely would cause a device bootup issue. The 1.8V VIOIN leakage due to early power-on of 3.3V can lead to:

    • Incorrect power-up behavior or even "soft" hangs if devices are configured with 1.8 voltage during reset.
    • Inconsistent state for chip peripherals such as clocks, counters.
    • Possible damage to sensitive analog circuits on low-voltage nodes.

    Hope this helps,

    E. Shareef