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LMK04821: LMK04821

William Wyatt-Millington
Prodigy 30 points
Part Number: LMK04821

Not clear from data sheet if the clock group supplies, VCC12_CG0, VCC2_CG1, VCC4_CG2 and VCC_CG3 can be different to other supplies, i.e. can you set a clock group supply to 1.8V to match supply to device providing clock sink?

  • 0
    TI__Genius 10995 points

    Hello William,

    You should be able to supply different voltages to the chip; however, when you turn your voltage supplies on, you want the lag between that toggle to be almost inexistent. The lag should not be any higher than a few ms. Another important note is that any power supply needs to be a minimum of 3.3 V, if not, it won't power that section of the chip, which will lead to incorrect behavior from the chip. Therefore, the 1.8 V you mentioned is not sufficient tp power any/all sections of the device.

    To further expand on using different power supplies, do keep in mind that in the evaluation module (EVM) TI developed and the example application on p. 112 of the data sheet, we use the same power supply for all the voltage groups. Also, the clock outputs do not have an internal regulator, so a clean power supply with sufficient output current capability is required for optimal performance.

    Good Luck,

    Andrea