10.1 Layout Guidelines

As with all PWM controllers, the effectiveness of the filter capacitors on the signal pins depends upon the integrity of the ground return. The pin out of the UCC28019A is ideally suited for separating the high di/dt induced noise on the power ground from the low current quiet signal ground required for adequate noise immunity. A star point ground connection at the GND pin of the device can be achieved with a simple cut out in the ground plane of the printed circuit board. As shown in Figure 34, the capacitors on ISENSE, VINS, VCOMP, and VSENSE must all be returned directly to the quiet portion of the ground plane, indicated by Signal GND, and not the high current return path of the converter, shown as the Power GND. Because the example circuit in Figure 34 uses surface mount components, the ICOMP capacitor, C10, has its own dedicated return to the GND pin.

10.2 Layout Example

Figure 34. Recommended Layout for the UCC28019A