Applications information

TDA7493

12/30

Doc ID 14570 Rev 6

5.3

Input resistance and capacitance

The input impedance is set by an internal resistor, Ri, of value 60 k

Ω. An input coupling

capacitor (Ci) is required on each input line. These two components together form a

high-pass filter whose cutoff frequency is:

Figure 4.

Input high-pass RC filter

The value of Ci is chosen depending on the application and the speaker system. For a

cut-off frequency less than 20 Hz, the input capacitors could be 470 nF each.

If a polarized capacitor is used, it is important to connect the positive side of the capacitor to

Figure 5.

Device input structure

Ri

Rf

Rf

Ri

Ci

Ci

Input signal

+

-