A large amount of power may be dissipated by the
UCC21220 and UCC21220A if the driving
voltage is high, the load is heavy, or the switching frequency is high (refer to
Section 9.2.2.4 for more details). Proper PCB layout can help dissipate heat from the device
to the PCB and minimize junction to board thermal impedance
(θJB).
Increasing the PCB copper connecting to VDDA,
VDDB, VSSA and VSSB pins is recommended, with priority on maximizing the
connection to VSSA and VSSB (see Figure 11-2 and Figure 11-3). However, high voltage PCB considerations mentioned above must be
maintained.
If there are multiple layers in the system, it is also recommended to connect the VDDA, VDDB, VSSA and VSSB pins to internal ground or power planes through multiple vias of adequate size. Ensure that no traces or coppers from different high-voltage planes overlap.