XLAMP® CMB1306 LED

© 2022 Cree LED. The information in this document is subject to change without notice. Cree®, the Cree logo, XLamp®, and EasyWhite® are registered

trademarks, and the Cree LED logo is a trademark, of Cree LED.

CLD-DS280

REV 0

22

THERMAL DESIGN

The CMB 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 LED has intentionally removed junction-temperature-based operating limits and replaced the commonplace

maximum T

J calculations with maximum ratings based on forward current (IF) and case temperature (Tc). No additional calculations

are required to ensure that the CMB LED is being operated within its designed limits. LES temperature measurement provides additional

verification of good thermal design. Please refer to page 4 for the Operating Limit specifications.

There is no need to calculate for T

J inside the package, as the thermal management design process, specifically from solder point (TSP)

to ambient (T

a), remains identical to any other LED component. For more information on thermal management of XLamp LEDs, please

refer to the Thermal Management application note. For CMB soldering recommendations and more information on thermal interface

materials (TIM), LES temperature measurement, and connection methods, please refer to the XLamp CM Family LEDs soldering and

handling document.

To keep the CMB1306 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.

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).

R_j-c

Tc

R_tim

R_hs

Ta

R_j-c

Tc

R_c-a

Ta

CMB1306-18V

0.01

0.10

1.00

10.00

100.00

200

300

400

500

600

700

800

900

1000

1100

1200

Current (mA)

Ta = 25 °C

Ta = 55 °C

Ta = 85 °C

Ta = 105 °C

18 V