TDA7493 Datasheet, PDF (19/30 Pages) STMicroelectronics – 3-watt + 3-watt dual BTL class-D audio amplifier

TDA7493
Applications information
The disadvantages of the anti-pop configuration are given below:
z The input impedance or the load of audio source is no longer 2 * Rin as in the case of
differential input configuration but R0. It means the load effect should be considered
during the application design. At this point, bigger R0 is better because of the lower
load effect.
z The input signal is also equivalent to
V_{in_actual} = V_in * 2 * Rin * (Rin + Rfb + R0) / (2 * Rin * (Rin + Rfb + R0) + Rfb * R0), not
the original V_in which means the actual gain is reduced.
When Rin = 30 kΩ, Rfb = 30 kΩ and R0 = 20 kΩ, the gain is reduced by 1 dB.
When Rin = 30 kΩ, Rfb = 120 kΩ and R0 = 20 kΩ, the gain is reduced by 1.84 dB. In
this case, smaller R0 is better.
If the pop noise is not critical, the anti-pop configuration can be simplified as shown in
Figure 14. The suggested value of the resistor R0 is 20 kΩ.
Figure 14. Simple anti-pop configuration for single-ended input application
TDA7493
Rfb
Cin
OUTP
INP
+
Rin
R0
Cin
GND
INN
-
Rin
Rfb
Input stage
Doc ID 14570 Rev 6
19/30