Design guidelines for schematic and PCB layout

AN3383

18/29

Doc ID 018691 Rev 1

Damping network

The C-R-C is a damping network. It is mainly intended for high inductive loads.

Figure 24.

Damping network

Main filter

The main filter is an L and C based Butterworth filter. The cutoff frequency must be chosen

between the upper limit of the audio band (

≈20 kHz) and the carrier frequency (384 kHz).

Figure 25.

Main filter

Recommended values

Table 2.

Recommended values

16

Ω

12

Ω

8

Ω

6

Ω

4

Ω

47 µH

33 µH

22 µH

15 µH

10 µH

220 nF

330 nF

470 nF

680 nF

1 µF

C dump-S

100 nF

100 nF

100 nF

100 nF

220 nF

C dump-P

100 nF

100 nF

100 nF

100 nF

220 nF

R dump

10

8.2

6.2

4.7

2.7

C dump-S

C dump-P

C dump-P

C dump-S

R dump

Rdump

AM045253v1

load

cutoff

load

R

f

C

*

*

*

2

1

Π

=

cutoff

f

R

L

load

load

*

2

*

*

2

Π

=

load

load

cutoff

L

C

f

*

*

2

*

*

2

1

Π

=

Rload

C load

Lload

Lload

INxA

INxB

AM045254v1