TDA7560
Figure 15. Power dissipation vs. ouput power
(Music/Speech Simulation)
Figure 16. Power dissipation vs. output power
(Music/Speech Simulation)
Ptot(W)
60
Ptot(W)
30
Vs= 13.2V
55
RL=4x 2Ohm
Vs=13.2V
GAUSSIAN NOISE
50
25
20
15
10
5
RL=4 x 4Ohm
45
GAUSSIANNOISE
CLIP START
40
35
30
25
20
15
10
5
CLIP START
0
2
4
6
8
10
0
1
2
3
4
5
6
Po(W)
Po(W)
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.
About the stand-by, the time constant to be as-
signed in order to obtain a virtually pop-free tran-
sition has to be slower than 2.5V/ms.
APPLICATION HINTS (ref. to the circuit of fig. 1)
SVR
Besides its contribution to the ripple rejection, the
SVR capacitor governs the turn ON/OFF time se-
quence and, consequently,plays an essential role
in the pop optimization during ON/OFF tran-
sients.To conveniently serve both needs, ITS
µ
MINIMUM RECOMMENDED VALUE IS 10 F.
HEATSINK DEFINITION
INPUT STAGE
Under normal usage (4 Ohm speakers) the
heatsink’s thermal requirements have to be de-
duced from fig. 15, which reports the simulated
power dissipation when real music/speech pro-
grammes are played out. Noise with gaussian-
distributed amplitude was employed for this simu-
lation. Based on that, frequent clipping occurence
(worst-case) will cause Pdiss = 26W. Assuming
Tamb = 70°C and TCHIP = 150°C as boundary
conditions, the heatsink’s thermal resistance
should be approximately 2°C/W. This would avoid
any thermal shutdown occurence even after long-
term and full-volume operation.
The TDA7560’s inputs are ground-compatibleand
can stand very high input signals (± 8Vpk) without
any performancesdegradation.
If the standard value for the input capacitors
µ
(0.1 F) is adopted, the low frequency cut-off will
amount to 16 Hz.
STAND-BY AND MUTING
STAND-BY and MUTING facilities are both
CMOS-COMPATIBLE. If unused, a straight con-
nection to Vs of their respective pins would be ad-
missible. Conventional low-power transistors can
8/10
STMICROELECTRONICS [ ST ]
