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LMK04826: Low-Power Condition

Shinichi Yokota
Genius 9715 points

Part Number: LMK04826

Hello,

How can I get a LMK04826 into a low-power condition? The power consumption of a system where the LMK04826 is used is required to be as low as possible when the system is in an idle state.

Besides, how much will the current consumption of the LMK04826 be in this low-power state? Is ICC_PD — Power down supply current the spec?

Best regards,
Shinichi Yokota

  • 0
    TI__Mastermind 18780 points

    Hi Shinichi,

    This device does not have a specific low-power mode but there is a general device power-down function controlled by register R2 (address 0x0002, set value to 1 for master power-down). I believe ICC_PD should describe this situation.

    I have not used this power-down function before but I assume it turns off as many device subsystems as possible. Most likely the I2C/SPI communication system is still active so that the device can be turned on again with another register write. The customer can also manually turn off subsystems such as the PLLs, inputs, and output drivers if they want more control but using R2 should be less work.

    Best,

    Evan Su

  • 0 in reply to Evan Su
    TI__Genius 9715 points

    Evan,

    Thanks for your quick feedback. Is the SPI register the only way to activate the power-down function? Can a hardware pin of the LMK04826 work as the control pin?

    Best regards,
    Shinichi Yokota

  • 0 in reply to Shinichi Yokota
    TI__Genius 12690 points

    Hi Shinichi-san,

    LMK04826 has power down option through SPI only. There is not HW control pin for power down.

    Thanks!

    Regards,

    Ajeet Pal

  • 0 in reply to Ajeet Pal
    TI__Genius 9715 points

    Ajeet,

    I'd like to ask one more question. The LMK04826 has a RESET pin on pin No. 5, but what's the function of this RESET pin? Doesn't it activate the low-power function?

    Best regards,
    Shinichi Yokota

  • 0 in reply to Shinichi Yokota
    TI__Genius 12690 points

    Hi Shinichi-san,

    RESET pin or RESET SPI bit, reset the device and set the register with it's POR setting. RESET will not activate the power down.

    Thanks!

    Regards,

    Ajeet Pal

  • 0 in reply to Ajeet Pal
    TI__Genius 9715 points

    Pal,

    By the way, what's the current consumption of the LMK04826 in its RESET state?

    Best regards,
    Shinichi Yokota

  • 0 in reply to Shinichi Yokota
    TI__Mastermind 18780 points

    Hi Shinichi-san,

    I am not sure if we have this information on hand because the RESET pin is not intended to be held high for long periods of time. Assuming that it only clears and resets the register subsystem and does not affect the PLLs or output drivers, then it will not save much power compared to normal. Ajeet would know better and will get back to you next week.

    Best,

    Evan Su

  • 0 in reply to Evan Su
    TI__Genius 12690 points

    Hi Shinichi-san,

    As Evan explained, with the reset the registers set to the POR settings and those are not much to reduce to the current consumption.

    Once you readback the registers after RESET, you can get the POR setting and the current consumptions for these settings would be around 376.4mA.

    Thanks!

    Regards,

    Ajeet Pal