troubleshooting of produced prototype: nrf9160

[David]

Hello,

I have developed 10pcs of one prototype with the nrf9160 SiP. 

I have some questions regarding some errors im having.

Regarding the SIM 1V8 driver VCC, for UICC interface, I am observing a fluctuation on this channel/voltage, from 0V -> 0.4 VDC, with approximately 1hz frequency.

What can cause this to happend, what is the normal behaviour of this channel when it is short-circuited with ground or something else/similar ?

My second question is regarding the attached image, im observing this on a few of my prototypes, im not able to upload any modem firmware to the SiP, any idea why?

Regards,

David

[David]

Hi,

I understand.

I just came over these posts, 

https://devzone.nordicsemi.com/f/nordic-q-a/55241/not-getting-1-8-volt-on-the-sim_1v8-pin-on-custom-board

maybe this is firmware related?, anything I should know about before I do further investigations on this?

Regards, David

[Andreas]

Hi,

 

By the way, your application does use the modem, right? If not, could you try running a sample that uses the modem? (the modem FW has to enable the power supply for the SIM)

 

Best regards,

Andreas