TS2007FC View Datasheet(PDF) - STMicroelectronics
Part Name
Description
Manufacturer
TS2007FC
STMicroelectronics
TS2007FC Datasheet PDF : 28 Pages
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TS2007FC
Application information
4.10
Output filter considerations
The TS2007 is designed to operate without an output filter. However, due to very sharp
transients on the TS2007 output, EMI radiated emissions may cause some standard
compliance issues.
These EMI standard compliance issues can appear if the distance between the TS2007
outputs and loudspeaker terminal are long (typically more than 50 mm, or 100 mm in both
directions). As the PCB layout and internal equipment device are different for each
configuration, it is difficult to provide a one-size-fits-all solution.
However, to decrease the probability of EMI issues, there are several simple rules to follow.
● Reduce, as much as possible, the distance between the TS2007 output pins and the
speaker terminals.
● Use a ground plane for shielding sensitive wires.
● Place, as close as possible to the TS2007 and in series with each output, a ferrite bead
with a rated current of minimum 2.5 A and impedance greater than 50 Ω at frequencies
above 30 MHz.
● Allow extra footprint to place, if necessary, a capacitor to short perturbations to ground
(Figure 45).
Figure 45. Ferrite chip bead placement
From TS2007 output Ferrite chip bead
to speaker
about 100pF
gnd
In the case where the distance between the TS2007 output and the speaker terminals is too
long, it is possible to have low frequency EMI issues due to the fact that the typical operating
PWM frequency is 280 kHz and fall and rise time of the output signal is less than or equal to
5 ns. In this configuration, it is necessary to use the output filter represented in Figure 46 on
page 24, that consists of L1, C1, L2 and C2 as close as possible to the TS2007 outputs.
When an output filter is used and there exists a possibility to disconnect a load, it is
recommended to use an RC network that consists of C3 and R as shown in Figure 46 on
page 24. In this case, when the output filter is connected without any load, the filter acts like
a short circuit for input frequencies above 10 kHz. The RC network corrects frequency
response of the output filter and compensates this limitation.
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