TS4962M

Application Information

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We have following equations:

In general, for mixed situations (single-ended and differential inputs) we must use the same

rule: equalize impedance on both TS4962M inputs.

5.10

Output filter considerations

The TS4962M is designed to operate without an output filter. However, due to very sharp

transients on TS4962M output, EMI radiated emissions may cause some standard compliance

issues.

These EMI standard compliance issues can appear if the distance between the TS4962M

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

directions, to the speaker terminals). As each 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 TS4962M output pins and the

speaker terminals.

●

Uses ground plane for “shielding” sensitive wire.

●

Place, as close as possible to the TS4962M and in series with each output, a ferrite bead

with a rated current at minimum 2A and impedance greater than 50

Ω at frequencies

>30MHz. If, after testing, these ferrite beads are not necessary, replace them by a short-

circuit. Murata BLM18EG221SN1 or BLM18EG121SN1 are possible examples.

●

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

following schematic).

In the case where distance between TS4962M's output and speaker terminals is high, it's

possible to have low frequency EMI issues due to the fact that the typical operating frequency is

250kHz.

In this configuration, utilization of the output filter represented in page 3 and close of the

TS4962M is necessary.

Out

+

Out

-

–

V

e1

300

R

in1

-------------

×… V

ek

300

R

ink

-------------

×

(V)

++

=

C

eq

k

Σ

j1

=

C

inj

=

C

inj

1

2

inj

F

×

×

×

CLj

----------------------------------------------------

(F)

=

R

eq

1

1

R

inj

----------

j1

=

k

∑

-------------------

=

Ferrite chip bead

about 100pF

Gnd

From TS4962 output

To speaker