I am currently working on a design with the nRF9160, and have a few questions about the DEC0 pin and decoupling for the module in general. I have been considering adding additional ceramic capacitors in the pF and nF range to the DEC0, VDD1 and VDD2 pins (to filter high frequency noise), but would like to know if this is recommended or not. My questions are as follows:
- Is the DEC0 pin used as decoupling for the power supply for the processor and peripherals, or is this pin used as decoupling for the power amplifier for the RF interface, or both?
- Is there any reason why I might want to add additional capacitance outside of the recommended 4.7 uF to the VDD1 and VDD2 pins, particularly capacitance in the pF and nF range?
- Are there any recommended capacitor specifications that should be considered when choosing these decoupling caps (ie. tolerance, voltage ratings, etc.)
Thanks in advance for any clarification!