The TPS40170 is designed for operation from an input voltage supply range
between 4.5 V and 60 V. Good regulation of this input supply is essential. If the
input supply is more distant than a few inches from the TPS40170 and the buck power
stage, the circuit can require additional bulk capacitance in addition to ceramic
bypass capacitors. An electrolytic capacitor with a value of 120 µF is a typical
choice.