TDA7350A_05 Datasheet, PDF (19/23 Pages) STMicroelectronics – 22W BRIDGE-STEREO AMPLIFIER FOR CAR RADIO

Figure 47.
TDA7350A
5.5 Balance Input In Bridge Configuration
A helpful characteristic of the TDA7350A is that, in bridge configuration, a signal present on both the input
capacitors is amplified by the same amount and it is present in phase at the outputs, so this signal does
not produce effects on the load.The typical value of CMRR is 46 dB.
Looking at fig 48, we can see that a noise signal from the ground of the power amplifier to the ground of
the hypothetical preamplifier is amplified of a factor equal to the gain of the amplifier (2 · Gv). Using a con-
figuration of fig. 49 the same ground noise is present at the output multiplied by the factor 2 · Gv/200.
This means less distortion,less noise (e.g. motor cassette noise ) and/or a simplification of the layout of
PC board.
The only limitation of this balanced input is the maximum amplitude of common mode signals (few tens of
millivolt) to avoid a loss of output power due to the common mode signal on the output, but in a large num-
ber of cases this signal is within this range.
5.6 High Gain, Low Noise Application
The following section describes a flexible preamplifier having the purpose to increase the gain of the
TDA7350A.
Figure 48.
Figure 49.
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