Application hints

TDA7381

12/15

Doc ID 4947 Rev 8

3.5

Stability and layout considerations

If properly layouted and hooked to standard carradio speakers, the TDA7381 will be

intrinsically stable with no need of external compensations such as output R-C cells. Due to

the high number of channels involved, this translates into a very remarkable components

saving if compared to similar devices on the market.

To simplify pc-board layout designs, each amplifier stage has its own power ground

externally accessible (pins 2,8,18,24) and one supply voltage pin for each couple of them.

Even more important, this makes it possible to achieve the highest possible degree of

separation among the channels, with remarkable benefits in terms of cross-talk and

distortion features.

About the layout grounding, it is particularly important to connect the AC-GND capacitor (C5)

to the signal GND, as close as possible to the audio inputs ground: this will guarantee high

rejection of any common mode spurious signals.

The SVR capacitor (C6) has also to be connected to the signal GND. Supply filtering

elements (C7, C8) have naturally to be connected to the power-ground and located as close

as possible to the Vs pins.

Pin 1, which is mechanically attached to the device’s tab, needs to be tied to the cleanest

power ground point in the pc-board, which is generally near the supply filtering capacitors.

Figure 10.

An example of circuit able to distinguish between the two occurrences