SLUS829G August 2008 – February 2020 UCC2897A
This pin serves as a dedicated connection to all high-current circuits inside the UCC2897A. The high-current portion of the controller consists of the two high-current gate drivers, and the various bias connections except VREF (pin 4). The PGND (pin 11) and GND (pin 6) pins are not connected internally, a low-impedance external connection between the two ground pins is also required. TI recommends to form a separate ground plane for the low-current setup components (RDEL, RON, ROFF, CVREF, CF, RSLOPE, CSS and the emitter of the optocoupler in the feedback circuit). This separate ground plane (GND) should have a single connection to the rest of the ground of the power converter (PGND) and this connection should be between pin 6 and pin 11 of the controller.