10 Power Supply Recommendations

During the turn-on and turn-off switching transient, peak source and sink currents are provided by the VDD and VEE power supply. The large peak current is possible to drain the VDD and VEE voltage level and cause a voltage droop on the power supplies. To stabilize a power supply and ensure reliable operation, a set of decoupling capacitors are recommended at the power supplies. Considering the UCC21738-Q1 has ±10-A peak drive strength and can generate high dV/dt, a 10-µF bypass capacitor is recommended between VDD and COM, VEE and COM. A 1-µF bypass capacitor is recommended between VCC and GND due to less current comparing with output side power supplies. A 0.1-µF decoupling capacitor is also recommended for each power supply to filter out high frequency noise. The decoupling capacitors must be low ESR and ESL to avoid high frequency noise, and should be placed as close as possible to the VCC, VDD, and VEE pins to prevent noise coupling from the system parasitics of PCB layout.