Layout

AN4569

22/29

DocID026803 Rev 1



Vcc filter for high frequency

The purpose of this filter is to avoid an inductive coil generated by the copper wire because

the system is working in PWM with fast switching (the frequency is about 340 kHz) so the

longer copper wire can easily become an inductor. To improve this we recommend using a

ceramic capacitor to balance the reactance. The ceramic capacitor must be placed as close

as possible to the related pins. The recommended distance between the capacitor to the

related pins is 5 mm maximum.



Decoupling capacitors

Solder the decoupling capacitors as close as possible to the related IC pin, the purpose of

which is to reduce the inductive coil with copper wire (parasitic inductor).

Figure 23. Correct layout for decoupling capacitors