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CC3000 shut-down mode is drawing far more current than it should

JW3092
Prodigy 40 points

Hi,

We built exactly as per reference design (see below). On holding VBAT_SW_ENB low we expect 5uA as per daasheet but we are getting about 1-6mA and it varies from try to try. SPI_CS is high so that's all disabled.

We've removed modules from PCBs and remaining circuitry takes tiny amount of current.

We've hooked up 2 CC3000 modules with wire to test it by itself. 1.5mA when SPI grounded. 4.5mA with SPI IOs floating all tested at 3V (see photo below).

Any ideas?

  • 0
    Prodigy 100 points

    Hi.

    What is the status of this request, please?

    Our problem is still unresolved.

    Mike

  • 0 in reply to mikemillen
    TI__Mastermind 27390 points

    Hi JW,

    Instead of floating and grounded, have you tried matching the drive on the SPI_DIN, SPI_CS, and SPI_CLK to their respective default states (pullup/pulldown)? They are given on the datasheet: http://www.ti.com/lit/gpn/cc3000

    Regards,

    Aaron

  • 0 in reply to made4engineering
    Prodigy 100 points

    Thanks!

    The problem turned out to be that the IRQ & Data outputs float when the device is in shutdown.  Like all cmos, when they float between logic levels they pull lots of current.

    The cure is to ensure the outputs are pulled high when in shutdown.

    The data sheet makes no mention of this, which I regard as a serious omission.

  • 0 in reply to mikemillen
    Genius 4895 points

    Hello Mike,

    thanks for the hint!

    You mean by adding external hardware. Is this correct?

    Would resistors from IRQ & Data output to WL_EN be a solution?

    Do you think it would be an advantage to switch off power of CC3000 completely instead of using WL_EN pin?

    Best regards,

    Martin

  • 0 in reply to Marie Maurer
    Prodigy 100 points

    Hi Martin,

    Yes... all that's needed is to add pullups to Vdd on those 2 lines.

    In our case we just enabled the programmable pullups in the MSP430 we're using as host controller.

    You don't want to pullup to WL_EN... it's only while that's low that you need the pullups.  :)

    (The CC3000 o/ps float when it's in shutdown only)

    If we hadn't found a solution we had intended to switch the supply into the CC3000, but now the shutdown current I measured on 2 test samples was 0.6uA & 0.7uA... not worth adding a switch!

    Regards, Mike.

  • 0 in reply to mikemillen
    Prodigy 40 points

    Mike,

    I'm working with a Micropython PyBoard and a CC3000.

    I pull EN low and then high again after about 50 seconds.

    I can not get it to come back up after sleeping.

    Do you have the correct procedure to put it to sleep and wake it up again?

    Regards, Scott