Hi.
I have a custom board with a NRF9161. The nrf91's LTE block connects to the sim holder through a NX3DV2567HR switch and an TPD3F303DQDR ESD protection.
I'm using a very simple firmware just to confirm if all is working but I always get a "CEREG:90" response.
I've checked with an oscilloscope that the nrf9161 is sending the SIM_CLK signal at the beginning of the connection, but I never see any changes in the SIM_VCC pin (always at 0V). A stable 1.8V bus is feeding the VDD_GPIO. I've made this test in two different boards and got the same result.
Can anyone suggest any good strategy to debug and solve this?
Thank you all in advance.