Datasheet

LT6654
16
6654fd
For more information www.linear.com/LT6654
Figure 11a. LT6654 S6 Thermal Hysteresis –40°C to 125°C
Figure 11b. LT6654 LS8 Thermal Hysteresis –40°C to 125°C
DISTRIBUTION (ppm)
–150
0
NUMBER OF UNITS
10
20
30
40
50
–100
–50
6654 F11
0 100 15050
MAX AVG HOT CYCLE
25°C TO 125°C TO 25°C
MAX AVG COLD CYCLE
25°C TO –40°C TO 25°C
applicaTions inForMaTion
Figure 9. Maximum Allowed Power Dissipation of the LT6654
Figure 10. Typical Power Dissipation of the LT6654
TEMPERATURE (°C)
0
0
POWER (W)
0.1
0.2
0.6
0.5
0.4
0.3
0.7
20 40 60 80
6654 F09
100 120 140
T = 150°C
θ
JA
= 192°C/W
130mW
V
IN
(V)
0
0
POWER (W)
0.05
0.25
0.20
0.15
0.10
0.40
0.35
0.30
5 10 15
6654 F10
20 25 30 35 40
10mA LOAD
NO LOAD
335mW
Power Dissipation
The power dissipation in the LT6654 is dependent on V
IN
,
load current and the package. The LT6654 package has
a thermal resistance, or θ
JA
, of 192°C/W. A curve that
illustrates allowed power dissipation versus temperature
for the 6-lead SOT-23 package is shown in Figure 9. The
power dissipation of the LT6654-2.5 as a function of input
voltage is shown in Figure 10. The top curve shows power
dissipation with a 10mA load and the bottom curve shows
power dissipation with no load. When operated within
its specified limits of V
IN
= 36V and sourcing 10mA, the
LT6654-2.5 consumes about 335mW at room temperature.
The power-derating curve in Figure 9 shows the LT6654-
2.5 can only safely dissipate 130mW at 125°C, which is
less than its maximum power output. Care must be taken
when designing the circuit so that the maximum junction
temperature is not exceeded. For best performance, junc
-
tion temperature should be kept below 125°C.
Th
e LT6654 includes output current limit circuitry, as well
as thermal limit circuitry, to protect the reference from
damage in the event of excessive power dissipation. The
LT6654 is protected from damage by a thermal shutdown
circuit. However, changes in performance may occur as
a result of operation at high temperature.
6654 F11b
DISTRIBUTION (ppm)
0
NUMBER OF UNITS
3
2
1
5
4
6
25°C TO –40°C TO 25°C
AND 25°C TO 125°C TO 25°C
–40 –30
–20 –10 0 10 20 30 40