SLVSDV8 July 2017 TPS54424
The voltage reference system produces a precise ±0.85%, 0.6 V voltage reference over temperature by scaling the output of a temperature stable band gap circuit. The output voltage is set with a resistor divider from the output (VOUT) to the FB pin shown in Figure 26. It is recommended to use 1% tolerance or better divider resistors. Start with a fixed value for the bottom resistor in the divider, typically 10 kΩ, then use Equation 1 to calculate the top resistor in the divider. To improve efficiency at light loads consider using larger value resistors. If the values are too high the regulator is more susceptible to noise and voltage errors from the FB input current are noticeable. The minimum output voltage and maximum output voltage can be limited by the minimum on time of the high side MOSFET and bootstrap voltage (BOOT-SW voltage) respectively.