SNVA559C September 2012 – February 2019 LM2574 , LM2575-N , LM2575HV , LM2576 , LM2576HV , LM2577
High-frequency bypass capacitors are always recommended on the supply pins of IC devices, but if the devices are used in assemblies near switching converters bypass capacitors are absolutely required.
The components which perform the high-speed switching (transistors and rectifiers) generate significant EMI that easily radiates into PCB traces and wire leads.
To assure proper circuit operation, all IC supply pins must be bypassed to a clean, low-inductance ground (for details on grounding, see Section 3.2).