A ceramic bypass capacitor, C_BYP, with a minimum capacitance of 10 µF is recommended to be placed from V_IN to –V_OUT. C_BYP can help filter the input voltage and minimize interference with other circuits. The voltage rating of the capacitor must be taken into consideration because it will experience stress equal to the full voltage range between V_IN and V_OUT.

Consider that the inclusion of the bypass capacitor introduces an AC path from V_IN to V_OUT and might worsen the transient response. When V_IN is applied to the circuit, this dV/dt across C_BYP creates a current that must return to ground to complete the loop. This current might flow through the internal low-side body diode of the MOSFET and inductor to return to ground. For this case, it is recommended to have a Schottky diode between
–V_OUT and SYS_GND as in Figure 3-1. If large-line transients are expected, increase the output capacitance to keep the output voltage within acceptable levels.

It is also recommended that a capacitor, C_BULK, is placed at the input power supply to help dampen the high-frequency noise that can couple onto the circuit. An electrolytic capacitor with moderate ESR helps dampen any input supply ringing caused by long power leads. When using the TPSM5601R5HEVM, adding a C_BULK capacitor across V_IN and SYS_GND is recommended.

Figure 3-1 TPSM5601R5H Inverting Buck-Boost Schematic with Schottky Diode