SNVSBK2 September 2019 LP8733
The input capacitors CIN_BUCK0 and CIN_BUCK1 are shown in the Typical Applications. A ceramic input bypass capacitor of 10 μF is required for each phase of the regulator. Place the input capacitor as close as possible to the VIN_Bx pin and PGND_Bx pin of the device. A larger value or higher voltage rating improves the input voltage filtering. Use X7R type of capacitors, not Y5V or F. Also, the DC bias characteristics capacitors must be considered. The minimum effective input capacitance to ensure good performance is 1.9 μF per buck input at maximum input voltage including tolerances, ambient temperature range, and aging (assuming at least 22 μF of additional capacitance is common for all the power input pins on the system power rail). See Table 48.
The input filter capacitor supplies current to the high-side FET switch in the first half of each cycle and reduces voltage ripple imposed on the input power source. The low ESR of the ceramic capacitor provides the best noise filtering of the input voltage spikes due to this rapidly changing current. Select an input filter capacitor with sufficient ripple current rating. In addition, ferrite can be used in front of the input capacitor to reduce the EMI.
|MANUFACTURER||PART NUMBER||VALUE||CASE SIZE||DIMENSIONS L × W × H (mm)||VOLTAGE RATING|
|Murata||GCM21BR71A106KE22||10 µF (10%)||0805||2 × 1.25 × 1.25||10 V|