DC/DC converters have advantages and disadvantages compared to a Low Drop Out regulator (LDO) or a DC/DC Controller with external FETs. A DC/DC Converter with integrated FETs is usually more efficient than an LDO. An LDO’s efficiency is calculated by the output voltage divided by the input voltage. When the output voltage is very low in relation to the input voltage, LDOs are not practical. For 5 Vin and 1.2 Vout, the efficiency of an LDO is 24%. A typical DC/DC converter efficiency would be around 80-90%. Since a DC/DC converter is switching off and on quickly, noise is generated as the chopped signal is applied to an inductor and capacitor energy storage filter. LDOs do not switch, so they are quieter than a DC/DC converter. Since LDOs do not need an inductor to store energy, they take up less board space. DC/DC converters are easier to use than DC/DC controllers with external MOSFETs. Selecting and designing with MOSFETs can be cumbersome and require debug time. Additionally, the circuit board trace from the controller to the MOSFET is noise sensitive and a good layout is vital for the power supply to work properly. Many DC/DC converters are internally compensated and do not require extra components or calculations to determine stability of the power supply. Not only do DC/DC converters integrate the MOSFET, but many will eliminate the need for external resistors and capacitors in the feedback loop. Fewer components also save board area. DC/DC converters with the FETs integrated save time and money, but may have a cost adder associated with them. When the output current requirement is beyond the capabilities of DC/DC converters on the market, the designer has no choice but to use a DC/DC controller and design with larger power MOSFETs.