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MAX3223E: Can't use auto power down function

Haiwen Huang
Intellectual 1850 points
Part Number: MAX3223E

Tool/software:

Dears:

when customer use below circuit, they found MAX3223E can't use auto power down function, they need pull up forceon pin, then MAX3223E can work. Could you please help check if below circuit is ok ? Thanks.

  • 0
    Guru 297970 points

    The datasheet says:

    With auto-powerdown enabled, the device is activated automatically when a valid signal is applied to any receiver input.

    So what are the voltages at the RIN pins?

  • 0
    TI__Guru 63140 points

    Hi Haiwen,

    With FORCEON tied low and #FORCEOFF tied high in the schematic, the device the device should power down if the RIN pins are between 0.3V and -0.3V. If you don't want the auto-power down feature enabled, then you need to have both FORCEON and #FORCEOFF to be a logic high. 

    Can you get scopeshots of the Rin pin to verify if they are near GND when you expect the auto power down function to be activate? You can also try to probe the invalid pin to verify if the auto-power down caused the device to shutdown.

    -Bobby