SLUSDX1 September 2020 TPS563211
The undervoltage lockout (UVLO) can be adjusted using the external voltage divider network of R1 and R2. R1 is connected between VIN and the EN pin of the TPS563211 and R2 is connected between EN and GND. The UVLO has two thresholds, one for power up when the input voltage is rising and one for power down or brownouts when the input voltage is falling. For the example design, the supply should turn on and start switching when the input voltage increases above 6.6 V (UVLO start or enable). After the regulator starts switching, it must continue to do so until the input voltage falls below 5.7 V (UVLO stop or disable). Equation 11 and Equation 4 can be used to calculate the values for the upper and lower resistor values. For the stop voltages specified, the nearest standard resistor value for R1 is 174 kΩ and for R2 is 36.5 kΩ.