TDA8947J Datasheet, PDF (8/24 Pages) NXP Semiconductors – 4-channel audio amplifier (SE: 1 W to 25 W; BTL: 4 W to 50 W)

Philips Semiconductors
TDA8947J
4-channel audio amplifier
8.5 Built-in protection circuits
The TDA8947J contains two types of detection sensors: one measures local
temperatures of the power stages and one measures the global chip temperature. At
a local temperature of approximately 185 °C or a global temperature of approximately
150 °C, this detection circuit switches off the power stages for 2 ms. High impedance
of the outputs is the result. After this time period the power stages switch on
automatically and the detection will take place again; still a too high temperature
switches off the power stages immediately. This protects the TDA8947J against
shorts to ground, to the supply voltage and across the load, and against too high chip
temperatures.
The protection will only be activated when necessary, so even during a short-circuit
condition, a certain amount of (pulsed) current will still be flowing through the short,
just as much as the power stage can handle without exceeding the critical
temperature level.
9. Limiting values
Table 6: Limiting values
In accordance with the Absolute Maximum Rating System (IEC 60134).
Symbol Parameter
Conditions
Min
V_CC
supply voltage
operating
−0.3
no (clipping) signal ^[1] −0.3
V_I
input voltage
−0.3
I_ORM repetitive peak output
-
current
T_stg
storage temperature
non-operating
−55
T_amb ambient temperature
−40
P_tot
total power dissipation
-
V_CC(sc) supply voltage to guarantee
-
short-circuit protection
Max
Unit
+26
V
+28
V
V_CC + 0.3 V
4
A
+150
°C
+85
°C
69
W
24
V
[1] The amplifier can deliver output power with non clipping output signals into nominal loads as long as
the ratings of the IC are not exceeded.
10. Thermal characteristics
Table 7: Thermal characteristics
Symbol Parameter
R_th(j-a) thermal resistance from
junction to ambient
R_th(j-c) thermal resistance from
junction to case
Conditions
in free air
all channels driven
Value Unit
40
K/W
1.3
K/W
9397 750 10779
Preliminary data
Rev. 01 — 06 February 2004
© Koninklijke Philips Electronics N.V. 2004. All rights reserved.
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