SLUSDS3A March 2020 – January 2024 UCC21739-Q1
PRODUCTION DATA
During the turn on and turn off switching transient, the peak source and sink current is 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 the power supply and ensure a reliable operation, a set of decoupling capacitors are recommended at the power supplies. Considering UCC21739-Q1 has ±10A peak drive strength and can generate high dV/dt, a 10µF bypass cap is recommended between VDD and COM, VEE and COM. A 1µF bypass cap is recommended between VCC and GND due to less current comparing with output side power supplies. A 0.1µF decoupling cap 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.