Datasheet

-40 -20 0 20 40 60 80 100 120 140 160
0
0.2
0.4
0.6
0.8
1
1.2
1.4
POWER CAPABILITY (W)
TEMPERATURE (°C)
Operating area
Maximum thermal capability line (
SOIC
)
Maximum thermal capability line
(
MSOP)
P
D(MAX)
=
150°C ± 125°C
165°C/W
= 0.15W
P
D(MAX)
=
150°C ± 125°C
235°C/W
= 0.11W
P
D(MAX)
=
150°C ± 25°C
165°C/W
= 0.76W
P
D(MAX)
=
150°C ± 25°C
235°C/W
= 0.53W
P
D(MAX)
=
T
J(MAX)
- T
A
T
JA
LM7332
SNOSAV4A –APRIL 2008–REVISED MARCH 2013 www.ti.com
The table entries are normalized to V
S
2
/R
L
. To figure out the AC load current component of power dissipation,
simply multiply the table entry corresponding to the output waveform by the factor V
S
2
/R
L
. For example, with
±12V supplies, a 600Ω load, and triangular waveform power dissipation in the output stage is calculated as:
P
AC
= (46.9 x 10
−3
) · [24
2
/600] = 45.0 mW (1)
The maximum power dissipation allowed at a certain temperature is a function of maximum die junction
temperature (T
J(MAX)
) allowed, ambient temperature T
A
, and package thermal resistance from junction to ambient,
θ
JA
.
(2)
For the LM7332, the maximum junction temperature allowed is 150°C at which no power dissipation is allowed.
The power capability at 25°C is given by the following calculations:
For VSSOP package:
(3)
For SOIC package:
(4)
Similarly, the power capability at 125°C is given by:
For VSSOP package:
(5)
For SOIC package:
(6)
Figure 52 shows the power capability vs. temperature for VSSOP and SOIC packages. The area under the
maximum thermal capability line is the operating area for the device. When the device works in the operating
area where P
TOTAL
is less than P
D(MAX)
, the device junction temperature will remain below 150°C. If the
intersection of ambient temperature and package power is above the maximum thermal capability line, the
junction temperature will exceed 150°C and this should be strictly prohibited.
Figure 52. Power Capability vs. Temperature
When high power is required and ambient temperature can't be reduced, providing air flow is an effective
approach to reduce thermal resistance therefore to improve power capability.
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