Issue B.2 07/08

Page 12 of 14

OPTEK reserves the right to make changes at any time in order to improve design and to supply the best product possible.

OPTEK Technology Inc. —

1645 Wallace Drive, Carrollton, Texas 75006

Phone: (972) 323-2200 or (800) 341-4747 FAX: (972) 323-2396 visibleLED@optekinc.com www.optekinc.com

Lednium Series Optimal X

OVTL09LG3x Series

Typical elements in the conducting path and corresponding nominal thermal conductivities are:

Elements

w/mK

Epilayers

GaN/InGaN

150

Substrate

Sapphire

50

Die attach material

Conductive epoxy

10

Package

Silver plated copper

350

Solder

Solder (Sn/Ag/Cu)

35

Copper cladding

Copper

300

Note : Thermal conductivity is a physical constant. For the materials above, the respective contribution each makes

to the overall thermal resistance (R

Thermal Conductivity (TC) is defined to be the heat conducted in time (t), through thickness (T) in a direction normal

to a surface area (A), due to a temperature difference (

δT).

Therefore

TC= q/t x {T/[A x

δT]}

and

δT = [Q x T]/[A x TC]

where

δT = Temp. difference (K)

Q = Power (w)

T = layer thickness (m)

TC = Thermal Conductivity (w/mK)

Theoretical Calculation (for 1 watt dissipated in a cup product via a single 40mil die)

GaN

= 0.07 K

Substrate

= 1.2 K

Die attach

= 1

Package

= 0.19

Solder

= 0.4

Total Calculated

δT = 2.86K