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DAC8218: DAC8218 Digital input current

feng luo
Prodigy 140 points
Part Number: DAC8218

Dear all

I have a confusion about some parameters of DAC8218's digital IOs.

1. As for the GPIOn, in absolute ratings, it shows maximum current is 5mA. I want to know whether this is maximum output current or input current, or the logic driving current?

2. As for the USB/BTC, RSTSEL, etc. logic input pins, here the input current is only ±5uA, I want to know the meaning of this value. Should it be the input leakage current? Or should it be the maximum driving current, which means the master should provide 5uA driving current at least?

3. The datasheet mentioned that the digital IO pins should be pulled up to VDD, I want to know how to calculate the value of pull-up resistors.

Thanks.

  • 0
    TI__Genius 14220 points
    Hi Feng,

    Thank you for your query. Please find the answers below:

    1. The GPIO-n input current rating of 5mA max specifies the limit for the maximum sink capability of the GPIOs when they are low and draw current through a pull-up resistor from supply, for example. The max current from VMON is the current it can supply when it is sourcing.
    2. The input current rating for the given digital pins is the maximum current drawn from the source that is driving these inputs
    3. In order to calculate the pull-up resistors, you should consider the max sink rating i.e. 5mA and choose the resistor accordingly such that the current is well within this value. For example, if the supply is 5V, a resistor value to have a sink current of 1mA is 5k. You can use even a 10k resistor to draw even lesser current

    Regards,
    Uttam Sahu
    Applications Engineer, Precision DACs