MAX77643's efficiency depends on the working mode.
For example, if Vin=3.7V, Vout=1.8V, we need set it to Buck mode, then the efficiency will be like below. If set to Buck-Boost mode as default, the efficiency will be less than 80%.
For Vin=3.7V, Vout=5.0V, we need set it to Boost mode, then the efficiency will be like below. If set to Buck-Boost mode as default, the efficiency will be less than 60%.