2000 Feb 09
6
Philips Semiconductors
Product specification
2
×
25 W high efficiency car radio power
amplifier
TDA1563Q
LIMITING VALUES
In accordance with the Absolute Maximum Rating System (IEC 134).
THERMAL CHARACTERISTICS
Note
1. The value of R
th(c-h)
depends on the application (see Fig.3).
SYMBOL
PARAMETER
CONDITIONS
MIN.
MAX.
UNIT
V
P
supply voltage
operating
−
18
V
non-operating
−
30
V
load dump; t
r
>
2.5 ms
−
45
V
V
P(sc)
short-circuit safe voltage
−
18
V
V
rp
reverse polarity voltage
−
6
V
I
ORM
repetitive peak output current
−
4
A
P
tot
total power dissipation
−
60
W
T
stg
storage temperature
−
55
+150
°
C
T
vj
virtual junction temperature
−
150
°
C
T
amb
ambient temperature
−
40
−
°
C
SYMBOL
PARAMETER
CONDITIONS
VALUE
UNIT
R
th(j-c)
thermal resistance from junction to case
see note 1
1.3
K/W
R
th(j-a)
thermal resistance from junction to ambient
40
K/W
Heatsink design
There are two parameters that determine the size of the
heatsink. The first is the rating for the virtual junction
temperature and the second is the ambient temperature at
which the amplifier must still deliver its full power in the
BTL mode.
With a conventional BTL amplifier, the maximum power
dissipation with a music-like signal (at each amplifier) will
be approximately two times 6.5 W.
At a virtual junction temperature of 150
°
C and a maximum
ambient temperature of 65
°
C, R
th(vj-c)
= 1.3 K/W and
R
th(c-h)
= 0.2 K/W, the thermal resistance of the heatsink
should be:
Compared to a conventional BTL amplifier, the TDA1563Q
has a higher efficiency. The thermal resistance of the
heatsink should be:
150
65
–
2
6.5
×
----------------------
1.3
–
0.2
–
5 K/W
=
150
65
–
2
6.5
×
----------------------
1.3
–
0.2
–
5 K/W
=
1.7
145
65
–
2
6.5
×
----------------------
1.3
–
0.2
–
9 K/W
=
handbook, halfpage
3.6 K/W
0.6 K/W
3.6 K/W
virtual junction
OUT 1
OUT 1
case
3.6 K/W
0.6 K/W
3.6 K/W
OUT 2
OUT 2
MGC424
0.1 K/W
Fig.3 Thermal equivalent resistance network.
