Design guidelines for schematic and PCB layout

AN3383

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Doc ID 018691 Rev 1

4

Design guidelines for schematic and PCB layout

4.1

Schematic

4.1.1

Main driver for selection of components

The characteristics of the main driver are as follows:

●

●

dielectric is X7R

●

Vdd and Ground for PLL filter separated from the other power supply

●

Coil saturation current compatible with the peak current of application

4.1.2

Decoupling capacitors

For the decoupling capacitor(s), one decoupling system can be used per channel. The

decoupling capacitor must be as close as possible to the IC pins in order to avoid parasitic

inductance with the copper wire on the PC board.

4.1.3

Output filter

Figure 21.

Output filter

1.

The key function of a snubber network is to absorb energy from the reactance in the

power circuit. The purpose of the snubber RC network is to avoid unnecessary high

pulse energy such as a spike in the power circuit which is dangerous to the system.

C98

470n

C105

100n

C101

100n

C95

100n

C89

100n

C90

330p

C99

1000p

C103

1000p

L13

22u

L11

22u

C91

1000p

R37

6.2

R34

6.2

R36

20

INxA

INxB

1

2

J7

CON2

SNUBBER

Main Filter

Damping Network

AM045250v1