Datasheet
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V
P
2 P
L
R
L
(5)
P
SUP
V
CC
V
P
R
L
V
CC
I
CC(q)
(6)
P
DISS
(1 ) P
SUP
(7)
T
A
Max T
J
Max Θ
JA
P
Diss
(8)
− Power Dissipation − W
P
D
0
0.2
0.4
0.6
0.8
1
1.2
1.4
1.6
1.8
2
0 0.5 1 1.5 2 2.5 3 3.5
V
CC
= 15 V, R
L
= 32
V
CC
= 15 V,
R
L
= 64
V
CC
= 12 V,
R
L
= 64
V
CC
= 12 V, R
L
= 32
P
O
− Output Power − W
Mono Operation
TPA6120A2
SLOS431 – MARCH 2004
APPLICATION INFORMATION (continued)
Therefore,
P
L
= Power delivered to load (per channel)
P
SUP
= Power drawn from power supply
V
LRMS
= RMS voltage on the load
R
L
= Load resistance
V
P
= Peak voltage on the load
I
CC
avg = Average current drawn from the power supply
I
CC
(q) = Quiescent current (per channel)
V
CC
= Power supply voltage (total supply voltage = 30 V if running on a ±15-V power supply
η = Efficiency of a SE amplifier
For stereo operation, the efficiency does not change because both P
L
and P
SUP
are doubled. This effects the
amount of power dissipated by the package in the form of heat.
A simple formula for calculating the power dissipated, P
DISS
, is shown in Equation 7 :
In stereo operation, P
SUP
is twice the quantity that is present in mono operation.
The maximum ambient temperature, T
A
, depends on the heat-sinking ability of the system. θ
JA
for a 20-pin DWP,
whose thermal pad is properly soldered down, is shown in the dissipation rating table.
Figure 35. Power Dissipation vs Output Power
18