Minimum input current on GPIO input

[Viggomh]

Hi,

Trying to figure out the current requirement on GPIO input, can you point me in the correct direction in how to figure out how much input current the GPIO on nrf9160 need to keep a stable voltage?

Maximum source impedance or similar?

Best regards

Viggo

[Marte Myrvold]

Hi Viggo.

The electrical specification for the GPIO on nRF9160 can be found here.

Best regards,

Marte

[Viggomh]

Hi,

Thanks, but those are for Output right?  I was looking for input

Best regards,

Viggo

[haakonsh]

The input current is dependent on what you rise- and fall-time requirements are. In essence, the pin is just a capacitor that you charge/discharge and the amount of current applied determines how fast that happens. 

The real answer is that if you have a strict requirement you will have to measure it for yourself. 

Why do you need to know the minimum input current, are you spec'ing a pull-up resistor or something?

-Håkon

[Viggomh]

Hi, ok, that gave me a better understanding, thanks

What is defining the capacitance of the input so I can calculate tau?

Best regards

Viggo