TDA749313TR Datasheet, PDF (18/30 Pages) STMicroelectronics – 3-watt 3-watt dual BTL class-D audio amplifier

Applications information
TDA7493
5.8.1
Single-ended input application
To use the device with a single-ended source, one input is AC connected to ground (via a
capacitor) and the other input is connected to the audio source. This is designed as a fully
differential input. The input scheme is shown in Figure 12.
However, to avoid the start-up pop noise, it is important to equalize, as much as possible,
the charging currents in the positive and negative inputs. Any imbalance in these charging
currents will be amplified and result in the familiar turn-on pop.
Figure 12. Single-ended input application
TDA7493
Rfb
C_cii_nn
OUTP
INP
+
Rin
C_cii_nn
GND
INN
-
Rin
Rfb
Input stage
Since the input charging currents in the circuit of Figure 12 can be different it is necessary to
add two resistors, R0, as shown in the circuit of Figure 13. In this way the currents in the two
branches of the differential input are better balanced and this can lead to the elimination of
the turn-on pop noise.
Figure 13. Anti-pop configuration for single-ended input application
TDA7493
OUTP
R0
GND
Rfb
Cin
INP
+
Rin
Cin
INN
-
Rin
R0
Rfb
Input stage
18/30
Doc ID 14570 Rev 6