Maximum Power Dissipation Vs Free-Air Temperature - Texas Instruments THS7002 User Manual

General PowerPAD Design Considerations
6) The top-side solder mask should leave exposed the terminals of the
7) Apply solder paste to the exposed thermal pad area and all of the
8) With these preparatory steps in place, the THS7002 is simply placed in
The actual thermal performance achieved with the THS7002 in its PowerPAD
package depends on the application. In the example above, if the size of the
internal ground plane is approximately 3 inches 3 inches, then the expected
thermal coefficient,
power dissipation is shown in Figure 1–13 and is calculated by the following
formula:
P
D
Where:
P
D
T
MAX
T
A
JA
Figure 1–13. Maximum Power Dissipation vs. Free-Air Temperature
1-18
package and the thermal pad area with its holes. Any larger holes outside
the thermal pad area, but still under the package, should be covered with
solder mask.
operational amplifier terminals.
position and run through the solder reflow operation as any standard
surface-mount component. This results in a part that is properly installed.
, is about 27.8 C/W. For a given
JA
T –T
MAX A
JA
= Maximum power dissipation of THS7002 (watts)
= Absolute maximum junction temperature (150 C)
= Free-ambient air temperature ( C)
=
JC + CA
= Thermal coefficient from die junction to case (0.72 C/W)
JC
= Thermal coefficient from case to ambient air ( C/W)
CA
MAXIMUM POWER DISSIPATION
FREE-AIR TEMPERATURE
9
8
7
6
5
4
3
2
JA = 56.2 C/W
2 oz Trace and Copper Pad
1
without Solder
0
–40 –20 0 20
T A – Free-Air Temperature – C
vs
T j = 150 C
PCB Size = 3" x 3"
No Air Flow
JA = 27.9 C/W
2 oz Trace and
Copper Pad
with Solder
40 60 80 100
General Information
, the maximum
JA