Help understanding "amux" of a power management ic

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  • caphair
    Badcaps Legend
    • Nov 2011
    • 1249
    #1

    Help understanding "amux" of a power management ic

    I believe it's an analog multiplexer but I'm not 100% positive of its purpose.

    Reason I'm interested:
    Have an iphone with no display even with all the output voltages present from the display power ic u1501

    The 1.8v lcm_enable rail is 1.2v which should be 1.8v

    Only places that enable line goes to is u1501 and the amux part of u1202 which is the main power management ic for the phone.

    Removed u1501 the enable line is still at 1.2v so u1501 isn't pulling it down. Also removed the one capacitor on that line and still 1.2v so it has to be u1202

    I tried injecting another 1.8v to lcm_enable it pulled it up to 1.6v but still low and it produced half an image that was just a bunch of lines.

    So that amux must control data or something related to display, but I'm not sure. Before replacing u1202 I'm looking for any info about it first as I couldn't find any datasheets for it which is usually the case for iPhone parts
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