Application information

TS2012EI

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DocID026152 Rev 1

4.9

Output filter considerations

The TS2012EI is designed to operate without an output filter. However, due to very sharp

transients on the TS2012EI output, EMI-radiated emissions may cause some standard

compliance issues.

These EMI standard compliance issues can appear if the distance between the TS2012EI

outputs and loudspeaker terminal are long (typically more than 50 mm, or 100 mm in both

directions, to the speaker terminals). Because 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 TS2012EI output pins and the

speaker terminals.



Use a ground plane to "shield" sensitive wires.



Place, as close as possible to the TS2012EI and in series with each output, a ferrite

bead with a rated current of at least 2.5 A and an impedance greater than 50

at

frequencies above 30 MHz. If, after testing, these ferrite beads are not necessary,

replace them by a short-circuit.



Allow extra footprint to place, if necessary, a capacitor to short perturbations to ground

(Figure 40).

Figure 40. Ferrite chip bead placement

In the case where the distance between the TS2012EI 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 frequency is 280 kHz. In this configuration, it is necessary to use the output filter

represented in Figure 1 on page 5 as close as possible to the TS2012EI.

4.10

Short-circuit protection

The TS2012EI includes output short-circuit protection. This protection prevents the device

from being damaged in case of fault conditions on the amplifier outputs.

When a channel is in operating mode and a short-circuit occurs between two outputs of the

channel or between an output and ground, the short-circuit protection detects this situation

and puts the appropriate channel into standby. To put the channel back into operating mode,

it is necessary to put the channel’s standby pin to logical LO, and then back again to logical

HI and wake up the channel.

to speaker

about 100pF

gnd

Ferrite chip bead

From output