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WL1835MOD: Power up/power down timings for VBAT, VIO and SCLK?

AnBer
Mastermind 30090 points
Part Number: WL1835MOD

Team,

1) We provide some precise power up/down sequence and timings in :
WL18xxMOD HW intergration guide - SWRU437
http://www.ti.com/lit/ug/swru437/swru437.pdf

a) For (2) is there a timings specification between SCLK and WL/BT_EN?
What is the minimum timings for the SCLK rising edge to the Enable signal?

b) (5) tells that SCLK "can be supplied before VBAT/VIO".
Must the CLK be supplied before VBAT/VIO supplies? What minimum timings?

c) Can you clarify what you mean in (4) by "in immaterial"?

2) From the below doc:
Level shifting WL18xx IOS - SWRA448A
http://www.ti.com/lit/an/swra448a/swra448a.pdfIt says that the supply need to be stable:

d) Can you quantify what you mean by stable?
Is it enough to have the supply higher than VIO min and VBAT min for at least 10uS? or is there some specific requirements in term of stability/variation over time?

Thanks in advance,

Anthony

  • 0
    TI__Mastermind 29291 points
    Hi,

    Your query has been assigned to WL18xx hardware experts. We will get back to you soon.

    Best regards,
    Vihang
  • 0
    TI__Genius 12730 points
    Hi Anthony,

    Please see my response below:

    1) a) you can sue the 10us in this case as well. More clock details in 1b).
    b) The 32kHz clock like is a fail-safe like. That means that the clock can be running to this pin even if no voltage is supplied to the part. So you can bring this clock line up before or after the supply lines. So in this case no minimum timing. In normal operation the 32kHz clock will always be running as it is used for the sleep modes.
    C) The meaning here is that once the enable line is disserted, then you can bring down VIO or VDD in any order. Thee is no sequencing for this.

    2) d) When we refer to stable we are meaning that when you turn on VIA and VDD, you are final VDD/VIO value is with 95% of its final value. IF you have overshoot or undershoot for example you wan to make sure this is stable before you enable. For the CLK, when you turn it on (if it is not always running) you want to make sure that it reaches its min and max levels before you enable.

    I hope this helps.

    Thanks,
    Riz