• State TI Thinks Resolved
  • Locked Locked
  • Replies 3 replies
  • Answers 1 answer
  • Subscribers 40 subscribers
  • Views 294 views
  • Users 0 members are here
Support feedback
Options
Options
Related

This thread has been locked.

If you have a related question, please click the "Ask a related question" button in the top right corner. The newly created question will be automatically linked to this question.

Original question:

MSP430F5249: External Voltage Reference

WL1837MOD: Power-down sequence

Bhavesh Tailor
Intellectual 290 points

Part Number: WL1837MOD
Other Parts Discussed in Thread: WL1837

To whom it may concern,

We have the following power-down sequence to the WL1837.  Please could you confirm if the WL_EN signal (Blue trace) is acceptable?

If so, we will make the same change to the BT_EN to allow it de-assert on power-down in the same way.

Please confirm and look forward to your response.

Many Thanks,

Bhav

  • 0
    TI__Mastermind 35795 points
    Hi,
    You need to consult the datasheet and make sure you meet the shutdown requirements .

    "To perform the correct shut-down sequence, deassert (low) WL_EN while all the supplies to the device (VBAT, VIO, and slow clock) are still stable and available. The supplies to the chip (VBAT and VIO) can be deasserted only after both enable signals are deasserted (low)."

    section 5.4 lists min/typical/max values

    seems like VIO is disabled when WLAN_EN could be potentially in high state.

    Saurabh
  • 0 in reply to S
    Intellectual 290 points

    Hi Saurabh,

    Thank you for your prompt response.

    Section 5.2 states the VIH(min) = 1.365V, which when looking at the screenshot, shows the WL_EN to be below the value at least 1ms before VIO starts to fall.  So it seems to me that we can say that the WL_EN will not be interpreted by the input as a High state, but also, will not be guaranteed to be interpreted by the input as a Low state.  Would this be damaging to the module?  If so, what is the nature of the damage?

    Many Thanks,

    Bhav

  • 0 in reply to Bhavesh Tailor
    TI__Mastermind 35795 points
    Bhav,
    Yes, you can potentially damage the chip if power up/down sequence is not followed

    Thanks
    Saurabh