UCC28019P datasheet(22/48 Pages) TI

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Layout Guidelines

Cut out in

ground plane

Signal

GND

Power

GND

ICOMP

ISENSE

VINS

VCOMP

VSENSE

VCC

GATE

UCC28019

SLUS755 – APRIL 2007

APPLICATION INFORMATION (continued)

As with all PWM controllers, the effectiveness of the filter capacitors on the signal pins depends upon the

integrity of the ground return. The pinout of the UCC28019 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 27, the capacitors on ISENSE, VINS, VCOMP, and VSENSE

(C11, C12, C15, C17, and C16, respectively) 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 27 uses surface mount components, the ICOMP capacitor, C10, has its

own dedicated return to the GND pin.

Figure 27. Recommended Layout for the UCC28019

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