T E C H N I C A L I N F O R M A T I O N
Power Dissipation Derating
For operating at ambient temperatures above 25°C the device must be derated based on a 150°C
maximum junction temperature, TJMAX as given by the following equation:
(T
T )
A
−
JMAX
P
=
DISS
θ
JA
where…
DISS = maximum power dissipation
P
TJMAX = maximum junction temperature of TA2024
TA = operating ambient temperature
θJA = junction-to-ambient thermal resistance
Where θJA of the package is determined from the following graph:
vs Copper Area
ΘJA
50
40
30
20
10
Pdiss - 1.35W
Pdiss - 2W
Pdiss - 3.4W
0
1
2
3
4
5
6
Copper Area (square inches)
In the above graph Copper Area is the size of the copper pad on the PC board to which the heat slug
of the TA2024 is soldered. The heat slug must be soldered to the PCB to increase the maximum
power dissipation capability of the TA2024 package. Soldering will minimize the likelihood of an over-
temperature fault occurring during continuous heavy load conditions. The vias used for connecting
the heatslug to the copper area on the PCB should be 0.013” diameter.
Page 10
TA2024 Preliminary, Rev. 1.0
TRIPATH [ TRIPATH TECHNOLOGY INC. ]
