
XLAMP®CM FAMILY LED SOLDERING & HANDLING
© 2017-2023 Cree LED. The information in this document is subject to change without notice. Cree®, the Cree logo, XLamp®, and the Cree LED logo are
registered trademarks, and Pro9 is a trademark, of Cree LED. Other trademarks, product and company names are the property of their respective owners
and do not imply specic product and/or vendor endorsement, sponsorship or association. This document is provided for informational purposes only
and is not a warranty or a specication. For product specications, please see the data sheets available at www.cree-led.com.
CLD-AP240
REV 8 5
Cree LED has used Arctic Silver®adhesive and Timtronics Silver Ice thermal grease in reference designs with good results. There are a
number of TIMs available; some are listed in the Thermal Management of XLamp LEDs application note. There are a number of factors
in the decision to use a particular TIM including, but not limited to, cost, availability, ease of use and manufacturing techniques, and
recommending a specic TIM for any lighting application is out of the scope of this document.
Cree LED recommends securing CM family LEDs to a heat sink using the structure of the lamp or luminaire, thermally conductive epoxy,
which is discussed previously in this section, or an LED holder, which is discussed in the LED Connectors section. Regardless of attachment
method, Cree LED recommends following the manufacturer’s directions for application to achieve maximum thermal performance. Use
caution when securing CM family LEDs over relatively thick TIMs, such as thermal pads, to avoid catastrophic mechanical damage to the
LED.
CM family LEDs and thermal interface materials are secured either by screws through the pair of diagonally opposite screw holes or
by the use of an LED holder (see the section on LED Connectors). When using the screw holes to secure CM family LEDs, Cree LED
recommends #4 (/40) or M2.5 screws. Excessive torque may result in damage to the LED array. Factors that determine the appropriate
screw torque are the thickness, size and type of thermal interface material and the planarity of these materials as well as that of the heat
sink. Refer to the illustration on page 2 for the proper mounting method. The amount of torque that can safely be applied to mounting
screws is approximately 45newton‑centimeters (4inch‑pounds). To prevent loosening of screws during vibration or thermal cycles, Cree
LED recommends non-conductive lock washers or self-locking fasteners. Cree LED DOES NOT RECOMMEND the use of chemical thread
lockers to secure CM family LEDs as several of these compounds have been shown to be chemically incompatible with LEDs.
CASE TEMPERATURE MEASUREMENT POINT
XLamp CM family LED case temperature can be measured at either solder pad. Cree LED recommends attaching the thermocouple with
conductive epoxy.
LIGHT-EMITTING SURFACE TEMPERATURE MEASUREMENT
The light‑emitting surface (LES) of XLamp CM family LEDs is dened as the central region of the LED, which contains the encapsulated
chip array as shown below.
LES temperatures are measured using an infrared (IR) thermal imaging camera. IR cameras detect the infrared wavelength thermal
emission from an object’s surface, which is correlated to the surface temperature using the surface’s thermal emissivity. CM family LES
thermal emissivity is 0.98. Please consult the IR camera’s operating instructions for proper measurement settings and guidelines. Factors
that can affect the accuracy of IR thermal measurement include the distance to the object’s surface, image focus and ambient conditions.
LES