Current capability MAGPIO nRF9160

[JasperS]

Hi

We are using the nRF9160 to drive the SD pin of the QM14501 LNA, which would typically consume 740uA.
While the pin is driven high, I only measure 0.7V on the pin, so I was wondering what the current capabilities are of the MAGPIO pins?

This information doesn't seem to be stated in the product specification.

Best regards,

Jasper

[Martin Lesund]

Hi Jasper,
The modem GPIOs, MAGPIO0/1/2 are digital 1,8V general-purpose I/Os.
Please see Operating Conditions documentation for more info.

The MAGPIO pins can be used, for example, to control an external antenna tuner, or any other GPIOcontrolled device, whose state depends on modem's RF frequency. (RF front-end controls)

Also check out the MAGPIO configuration documentation on more information on how to configure them.

Please state in more detail what your setup is and what you are trying to achieve since I am not certain that you are using them correctly.

[JasperS]

Hi Martin,

I'm afraid you misunderstood my question, I'm wondering how much current the MAGPIO pins can source or sink.

Best regards,

Jasper

[Martin Lesund]

Hi Jasper,
Sorry for the misunderstanding.

I do not know the limit, but they should deliver more than enough. e.g. we have used the QM14501 on earlier revisions of the DK and it worked fine there.

I would suggest that you try to reflow your card, since I suspect that there is a tiny short somewhere, or cut the bridge between the MAGPIO-pin and LNA and see if it still is 0.7V or if it goes up to 1.8V. 
Do you have just one board or seeing this on several?

[JasperS]

Hi Martin,

It appeared the SD pin of the QM14501 LNA is not a digital input, but an analog gain control input, and can consume up to 20mA when directly connected to VDD. Unfortunately, there is close to zero information about all this in the datasheet, and Qorvo doesn't have any data about how much current it draws for which gain.

For now I've bodged some mosfets with a current limiting resistor and that seems to work decently.

Thank you for your support,

Jasper Smit