I have a processor based system that I would like to power with the ADP5034, since the system will enter periodically in low power mode, what is the best way to use the MODE pin?
The simplest way is to connect the MODE pin to ground, this will allow the buck regulators to enter automatically is power saving mode (PSM) if the load current is below ~100mA otherwise will operate in constant PWM operation. If your system contains circuit sensitive to the ripple noise generated by a buck regulator you may need to set the MODE pin to logic level high so that it will be forced to operate in PWM, in this mode the ripple amplitude will be drastically reduced and the frequency component will be mainly the switching frequency (3-MHz) easier to filter. The drawback is that the efficiency will be very low at light loads, if the processor controls or knows when this sensitive circuit operates you can consider connecting one of the processor’s GPIO to the MODE pin, in this way the processor can select when the buck can operate in one of the two modes. We always suggest to connect the MODE pin to a processor’s GPIO whereas possible, it may turn out useful if condition arise.