AN3387

PM8803 layout guideline

Doc ID 018735 Rev 1

7/12

1.5

In more detail

1.

Place the transient voltage suppressor (TVS) close to the input common mode filter, if

possible on the same side of the PCB

2.

Place the PM8803 and all the related components close to each other; use both sides

3.

Place all the feedback components close to each other, use both sides

4.

Place the sense resistors close to the Power MOSFET, if possible on the same side

5.

Place the input ceramic capacitors close to the input side of the power transformer, if

possible on the same side

6.

Place the primary snubber network close to the power transformer, on the bottom side

7.

Place the rectifier diode or MOSFET close to the output side of the transformer, if

possible on the same side

8.

Place the secondary snubber network close to the rectifier diode or MOSFET, bottom

side

9.

Place the first ceramic capacitors close to the rectifier diode and the power transformer,

on the copper areas, top side

10. Place the last ceramic capacitors close to the output of the power converter

11. Place the 100 nF input capacitor close to the VSS and GND pins

12. Place the decoupling capacitors for VC close to the PM8803 pin 6

13. Place the components for FRS, DT and DCCL pins in a quiet area, separated as much

as possible from the other signals

14. Use traces of at least 20 mils for the following PM8803 pins: GAT1, GAT2, VC, CLS

15. Connect the PM8803 pins RTN1, RTN2, VSS, VDD to the relevant board copper areas

16. Use a wide path or copper area for SA auxiliary circuitry