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The design uses a LM2727 synchronous controller utilizing external high side and low side N-channel MOSFETs operating at 600kHz. Operating the high frequency aids in minimizing the component size, thus resulting in overall smaller package. Careful PC board layout is critical to achieve low switching losses and clean, stable operation. The switching power stage requires particular attention. Few points to note for this design are:
1) Decoupling capacitors are close to IC pins as possible. Keep separate power ground plane.
2) Input and output capacitors are connected to the power ground plane; all other capacitors are connected to the signal ground plane.
3) High current paths are very short.
4) Multiple MOSFETs have been used to reduce the conduction and switching losses.
5) Feedback connections are short and direct and routed away from any noisy traces (i.e. switch node).
6) High-side MOSFETs are as close as possible to the controller
Notes:
Note that MOSFETs M1 and M2 in the schematic are represented as Q1 and Q2 in the layout.
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Example Schematic Showing Connection for all Components.
