9.2.2.7 Input Capacitor Selection

The LMR23630-Q1 device requires high-frequency input decoupling capacitor(s) and a bulk input capacitor, depending on the application. The typical recommended value for the high-frequency decoupling capacitor is 4.7 μF to 10 μF. TI recommends a high-quality ceramic capacitor type X5R or X7R with sufficiency voltage rating. To compensate the derating of ceramic capacitors, a voltage rating of twice the maximum input voltage is recommended. Additionally, some bulk capacitance can be required, especially if the LMR23630-Q1 circuit is not located within approximately 5 cm from the input voltage source. This capacitor is used to provide damping to the voltage spike due to the lead inductance of the cable or the trace. For this design, two 4.7-μF, 50-V, X7R ceramic capacitors are used. Use 0.1-μF for high-frequency filtering and place it as close as possible to the device pins.