CXA1304 Datasheet, PDF (27/30 Pages) Cree, Inc – XLamp LED

XLamp^® CXA1304 LED
Thermal Design
The CXA family of LED arrays can include over a hundred different LED die inside one package, and thus over a hundred different junction
temperatures (T_J). Cree has intentionally removed junction-temperature-based operating limits and replaced the commonplace maximum
T_J calculations with maximum ratings based on forward current (I_F) and case temperature (Tc). No additional calculations are required to
ensure the CXA LED is being operated within its designed limits. Please refer to page 2 for the Operating Limit specification.
There is no need to calculate for T_J inside the package, as the thermal management design process, specifically from solder point (T_SP) to
ambient (T_a), remains identical to any other LED component. For more information on thermal management of Cree XLamp LEDs, please
refer to the Thermal Management application note. For CXA soldering recommendations and more information on thermal interface
materials (TIM) and connection methods, please refer to the Cree XLamp CX Family LEDs soldering and handling document. The CX
Family LED Design Guide provides basic information on the requirements to use Cree XLamp CXA LEDs successfully in luminaire designs.
To keep the CXA1304 LED at or below the maximum rated Tc, the case to ambient temperature
thermal resistance (R_c-a) must be at or below the maximum R_c-a value shown on the following
graphs, depending on the operating environment. The y‑axis in each graph is a base 10 logarithmic
scale.
R_j-c
Tc
R_j-c
Tc
As the figure at right shows, the R_c-a value is the sum of the thermal resistance of the TIM (R_tim)
plus the thermal resistance of the heat sink (R_hs).
CXA1304-9V
100.00
R_tim
R_hs
Ta
R_c-a
Ta
10.00
1.00
0.10
9V
Ta = 25 °C
Ta = 55 °C
Ta = 85 °C
Ta = 105 °C
0.01
200
300
400
500
600
700
800
900
1000
Current (mA)
Copyright © 2013-2016 Cree, Inc. All rights reserved. The information in this document is subject to change without notice. Cree^®, XLamp^® and EasyWhite^® are registered trademarks and the Cree logo is a
trademark of Cree, Inc. UL^® and the UR logo are registered trademarks of UL LLC.
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