AN3383

Design guidelines for schematic and PCB layout

Doc ID 018691 Rev 1

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Figure 34.

copper wire because the system is working in PWM with fast switching (the frequency is

about 340 kHz) so the longer copper wire is very easy to become an inductor. To improve

this we suggest using ceramic capacitors to balance the reactance.

It is mandatory to put the ceramic capacitors as close as possible to the related pins. The

distance between the capacitor to the related pins is suggested to be within 5 mm.

Figure 35.

Decoupling capacitors

Solder the decoupling capacitors as close as possible to the related IC pin in order to reduce

the inductive coil with copper wire (parasitic inductor). As shown in Figure 35, the first

example is a correct layout while the second example is incorrect.

Place Vcc filter capacitors as close as possible

to the related pins, the ceramic capacitors on

top of the PCB near the IC due to SMD

mounting limitations.

AM045263v1

AM045264v1