Datasheet

16
Appendix A. Thermal Considerations
The display IC has a maximum junction temperature of
150°C. The IC junction temperature can be calculated
with Equation 1 in Table 3.
A typical value for Rθ
JA
is 100°C/W. This value is typical
for a display mounted in a socket and covered with a
plastic lter. The socket is soldered to a .062 inch thick
PCB with .020-inch wide, one ounce copper traces. P
D
can be calculated as Equation 2 in Table 3.
Figure 9 shows how to derate the power of one IC
versus ambient temperature. Operation at high ambient
temperatures may require the power per IC to be
reduced. The power consumption can be reduced by
changing the N, I
PIXEL
, Osc cyc or V
LED
. Changing V
LOGIC
has very little impact on the power consumption.
Figure 9. Maximum power dissipation per IC versus ambient temperature
P MAX – MAXIMUM POWER
DISSIPATION PER IC – W
D
0
25
T
A
– AMBIENT TEMPERATURE – °C
0.7
0.6
0.5
0.4
0.3
0.2
0.1
60555045403530
0.8
0.9
1.0
1.1
1.2
8580757065
R = 100°C/W
90
1.3
θ
J-A