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Original question:

TPS65224-Q1: TPS6522430 ADC ref. voltage tolerance

TPS65224-Q1: TPS65224-Q1 pin injection current

Momchil Haymanov
Prodigy 80 points
Part Number: TPS65224-Q1

Tool/software:

Hello there, 

what is the maximum allowed injection current into pin 11 (GPIO5) configured as ADC input ?

Regards, 

Momchil Haymanov

  • 0
    TI__Mastermind 20030 points

    Hi Momchil,

    the maximum leakage current into GPIO5 when configured as ADC_IN is 200uA as stated by the data sheet. This value applies when the pin is used according to the spec.

    regards,

    Niko 

  • 0 in reply to Niko Alatalo
    Prodigy 80 points

    The question is what is the maximal allowed injection current, not the leakage current. As per datasheet GPIO 5 is part of 1V8 domain, but the internal reference is 1.2V, if we apply voltage higher than 1.2V, but lower than 1V8+0.3V (assuming 0.3V is the forward voltage of on-ship diode) what will happen?

    If we never go beyond 2V on this pin, shall we limit the current to the pin?

    I want to use the lowest possible values for the resistor divider in order to limit the leakage error. 

    Regards, 

    Momchil Haymanov

  • +1 in reply to Momchil Haymanov
    TI__Mastermind 20030 points

    Hi Momchil,

    you don't need to limit the current to this pin as the input resistance is about 0.5Mohm. If you the voltage at this pin exceeds 1.2V you will have to have the internal divider enabled and in this scenario it is already specified that no more than 200uA will flow into this pin suggesting there is no need to limit the current. If you are using external divider I would suggest you divide the voltage to be below 1.2V at the pin so you don't need to enable the internal divider.

    regards,

    Niko