TDA8946 Philips Semiconductors, TDA8946 Datasheet - Page 16

• Manufacturer Part Number: TDA8946
• Description: 2 x 15 W stereo Bridge Tied Load BTL audio amplifier
• Manufacturer: Philips Semiconductors

15. Test information
Philips Semiconductors
9397 750 06863
Product specification
14.2 Thermal behaviour and heatsink calculation
15.1 Quality information
15.2 Test conditions
The measured maximum thermal resistance of the IC package, R
A calculation for the heatsink can be made, with the following parameters:
At V
see
dissipation - is: 150 – 50 = 100 C.
The calculation above is for an application at worst-case (stereo) sine-wave output
signals. In practice music signals will be applied, which decreases the maximum
power dissipation to approximately half of the sine-wave power dissipation (see
Section
To increase the lifetime of the IC, T
heatsink of approximately 4 K/W for music signals.
The General Quality Specification for Integrated Circuits, SNW-FQ-611D is
applicable.
T
unless otherwise specified.
Remark: In the graphs as function of frequency no bandpass filter was applied; see
Figure
amb
T
V
T
R
including the heatsink. In the heatsink calculations the value of R
P
R
R
P
R
R
amb(max)
j(max)
CC
th(tot)
th(tot)
th(h-a)
th(tot)
th(h-a)
CC
Figure
= 25 C; V
R
R
= 18 V and R
7,
= 12 V and R
th(tot)
th(tot)
8.2.2). This allows for the use of a smaller heatsink:
= 150 C.
is the total thermal resistance between the junction and the ambient
= 100/18 = 5.56 K/W
= 100/8 = 12.5 K/W
= R
= R
12
11. For T
= 50 C
and 13.
= 100 C
= 100 C
th(tot)
th(tot)
CC
– R
– R
Rev. 02 — 14 March 2000
= 18 V; f = 1 kHz; R
L
L
j(max)
= 8
th(j-mb)
th(j-mb)
= 8
= 150 C the temperature raise - caused by the power
= 5.56 – 4.5 = 1.06 K/W.
the measured worst-case sine-wave dissipation is 18 W;
= 12.5 – 4.5 = 8.0 K/W.
j(max)
L
should be reduced to 125 C. This requires a
= 8 ; audio pass band 22 Hz to 22 kHz;
2 x 15 W stereo BTL audio amplifier
© Philips Electronics N.V. 2000. All rights reserved.
TDA8946J
th(j-mb)
th(mb-h)
is 4.5 K/W.
is ignored.
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