The input side is the same as a buck circuit stage, the input cap design can reuse the positive application. In order to perform a low output voltage ripple,2.2-uf ceramic capacitors with low ESR are preferred, and it’s better to have X7R act as input and output side, consider the temperature characteristics and DC biases of capacitor. Also a high frequency capacitor 0.1-uf is recommend together with 2.2-uf 100-V input cap put very close to the pin.

High frequency bypass capacitor from Vin to Buck Vout, example as 0.1uf, this can improve the stability and reduce Vout ripple. Because the device GND is the power supply output voltage, the voltage rating of the capacitor must be greater than the differences in the maximum input and output voltage of the power supply, a 0.1-μF, 100-V ceramic capacitor is chosen here for high-frequency filtering and also place it as close as possible to the device pins.

The output capacitance can also follow buck converter data sheet recommendations, but might need to be increased to improve performance. Refer to different output voltage in Table 3-4 give out a min value, start from 22-μF, 25-V as a example.