LM53625-Q1: Input capacitor

Hello Tateo-san,

In addition to the explanation supplied in the device datasheet (section 9.2.1.2.1.1) following effects will be more pronounced:

1. with reduced input capacitance the input voltage ripple will be significantly higher.
2. This in turn will results in much higher conducted EMI noise on the board
3. reduced input capacitance will result in much larger input voltage dips during load transients, significantly affecting device performance
4. smaller input capacitance value will mean that these capacitor will have to handle larger ripple currents, potentially affecting the lifetime (reliability) of these components
5. line transients will be affected if input capacitance value is lower than recommended

In summary we strongly recommend placing at least minimum recommended amount of input capacitance on the PCB and follow recommended board layout guidelines as far as placement of the components is concerned.

Best regards

Brani