PRODUCT SPECIFICATION

RC5054A

7

Typical Application

+12V

PGND

RC5054

VSEN

RT

FB

COMP

VID0

VID1

VID2

VID3

SS

PGOOD

D/A

GND

OSC

LGATE

UGATE

OCSET

PHASE

BOOT

EN

VCC

OVP

MONITOR AND

PROTECTION

+

-

+

-

VID4

Applications Discussion

Layout Considerations

As in any high frequency switching converter, layout is very

important. Switching current from one power device to another

can generate voltage transients across the impedances of the

interconnecting bond wires and circuit traces. These intercon-

necting impedances should be minimized by using wide, short

printed circuit traces. The critical components should be

located as close together as possible, using ground plane

construction or single point grounding.

Figure 3 shows the critical power components of the converter.

To minimize the voltage overshoot the interconnecting wires

indicated by heavy lines should be part of ground or power

plane in a printed circuit board The components shown in

Figure 3 should be located as close together as possible. Please

physical capacitors. Locate the RC5054A within 3 inches of

the MOSFETs, Q1 and Q2. The circuit traces for the MOSFETs’

gate and source connections from the RC5054A must be

sized to handle up to 1A peak current.

Figure 3. Printed Circuit Board

Power and Ground Planes or Islands

Figure 4 shows the circuit traces that require additional

layout consideration. Use single point and ground plane

construction for the circuits shown. Minimize any leakage

close to the SS pin because the internal current source is only

10

to the BOOT and PHASE pins.

Figure 4. Printed Circuit Board

Small Signal Layout Guidelines

Feedback Compensation

Figure 5 highlights the voltage-mode control loop for a

synchronous-rectified buck converter. The output voltage

oscillator (OSC) triangular wave to provide a pulse-width

PHASE node. The PWM wave is smoothed by the output

PGND

LGATE

UGATE

PHASE

Q1

Q2

D2

RETURN

RC5054A

+12V

RC5054A

SS

GND

VCC

BOOT

D1

Q1

Q2

PHASE