7/10

TDA7388

Figure 13. Output Noise vs. Source

Resistance.

Figure 14. Power Dissipation & Efficiency vs.

Output Power.

5

APPLICATION HINTS

(ref. to the circuit of fig. 4)

5.1 SVR

Besides its contribution to the ripple rejection, the SVR capacitor governs the turn ON/OFF time sequence

and, consequently, plays an essential role in the pop optimization during ON/OFF transients. To conve-

niently serve both needs, ITS MINIMUM RECOMMENDED VALUE IS 10

µF.

5.2 INPUT STAGE

The TDA7388’S inputs are ground-compatible and can stand very high input signals (± 8Vpk) without any

performances degradation. If the standard value for the input capacitors (0.1

µF) is adopted, the low fre-

quency cut-off will amount to 16 Hz.

5.3 STAND-BY AND MUTING

STAND-BY and MUTING facilities are both CMOS-COMPATIBLE. If unused, a straight connection to Vs

of their respective pins would be admissible.

Conventional/low-power transistors can be employed to drive muting and stand-by pins in absence of true

CMOS ports or microprocessors. R-C cells have always to be used in order to smooth down the transitions

for preventing any audible transient noises.

Since a DC current of about 10

µA normally flows out of pin 22, the maximum allowable muting-series re-

sistance (R2) is 70K

Ω, which is sufficiently high to permit a muting capacitor reasonably small (about 1µF).

1.5 V threshold voltage and the device will consequently fail to turn OFF when the mute line is brought

down. About the stand-by, the time constant to be assigned in order to obtain a virtually pop-free transition

has to be slower than 2.5V/ms.