RE: Hardware connection to SIM880L module?

Michal — Wed, 19 Mar 2025 17:39:28 GMT

Hello,

I see lots of UART hardware design recommendations for different voltages on pages 30-32 in their datasheet.

[quote user=""]If I understand the sim800L spec sheet correctly, it will need its own power source because it requires 3.5~4.2V and 2A, which is too high for the nrf52840. So my plan was to connect the nrf52840dk 5V output to a lm2596 buck converter module that will convert that 5v down to 4V and then connect the converter to the SIM800L's VCC. I will then wire the nrf52840dk and SIM800L grounds together.[/quote]

I doubt that the DKs 5V pin will be able to supply 2A. If your USB is out of spec (or you're using an external charger), maybe, but the pin or traces leading to 5V may not like it (or you'll get a high voltage drops during transmission peaks).

Best regards,

Michal