For best output and input voltage filtering, low ESR X5R or X7R ceramic capacitors are recommended.

The input capacitor minimizes input voltage ripple, suppresses input voltage spikes and provides a stable system rail for the device. An input capacitor value of at least 10 μF is recommended to improve transient behavior of the regulator and EMI behavior of the total power supply circuit. A ceramic capacitor placed as close as possible to the VIN and GND pins of the IC is recommended. For applications where line transient is expected, an input filter composed of 400-Ω resistor and 0.1-μF capacitor as shown in Figure 9-1 is mandatory to avoid interference to internal pass-through threshold comparison circuitry.

For the output capacitor of VMAIN pin, small ceramic capacitors are recommended, placed as close as possible to the VMAIN and GND pins of the IC. If, for any reason, the application requires the use of large capacitors which cannot be placed close to the IC, the use of a small ceramic capacitor with a capacitance value of around 2.2 μF in parallel to the large one is recommended. This small capacitor should be placed as close as possible to the VMAIN and GND pins of the IC. The recommended typical output capacitor values are 10 μF and 22 μF (nominal values).

For LDO version, like all low dropout regulators, VSUB rail requires an output capacitor connected between VSUB and GND pins to stabilize the internal control loop. Ceramic capacitor of 10 μF (nominal value) is recommended for most applications. If the V_(SUB) drop during load transient is much cared, higher capacitance value up to 22 μF is recommended to provide better load transient performance. Capacitor below 10 μF is only recommended for light load operation. For load switch version, capacitor of 10x smaller value than capacitor at VMAIN pin is recommended to minimize the voltage drop caused by charge sharing when the load switch is turned on.

When selecting capacitors, ceramic capacitor’s derating effect under bias should be considered. Choose the right nominal capacitance by checking capacitor's DC bias characteristics. In this example, GRM188R60J106ME84D, which is a 10 μF ceramic capacitor with high effective capacitance value at DC biased condition, is selected for both VMAIN and VSUB rails. The load transient response performance is shown in Section 9.2.1.3.

For load switch version, VSUB rails requires an output capacitor connected between VSUB and GND pins. Ceramic capacitor of 1 μF (nominal value) is recommended for most applications.