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Data subject to change. Copyright © 2005-2015 Avago Technologies. All rights reserved.
AV02-2936EN - March 26, 2015
DISCLAIMER: Avago’s products and software are not specically designed, manufactured or authorized for sale
as parts, components or assemblies for the planning, construction, maintenenace or direct operation of a
nuclear facility or for use in medical devices or applications. Customer is solely responsible, and waives all rights to
make claims against avago or its suppliers, for all loss, damage, expense or liability in connection with such use.
T
S
can be measured easily by mounting a thermo-
couple on the soldering joint as shown in illustration
above, while R
qJ-S
is provided in the datasheet. User is
advised to verify the T
S
of the LED in the nal product
to ensure that the LEDs are operated within all maxi-
mum ratings stated in the datasheet.
5. Eye safety precautions
LEDs may pose optical hazards when in operation. It is
not advisable to view directly at operating LEDs as it
may be harmful to the eyes. For safety reasons, use ap-
propriate shielding or personal protective equipments.
6. Disclaimer
Avago’s products are not specically designed, manu-
factured or authorized for sale as parts, components
or assemblies for the planning, construction, mainte-
nance or direct operation of a nuclear facility or for
use in medical devices or applications. Customer is
solely responsible, and waives all rights to make claims
against Avago or its suppliers, for all loss, damage, ex-
pense or liability in connection with such use.
The complication of using this formula lies in T
A
and
R
qJ-A
. Actual T
A
is sometimes subjective and hard to de-
termine. R
qJ-A
varies from system to system depending
on design and is usually not known.
Another way of calculating T
J
is by using solder point
temperature T
S
as shown below:
T
J
= T
S
+ R
qJ-S
x I
F
x V
Fmax
where;
T
S
= LED solder point temperature as shown in illustra-
tion below [°C]
R
qJ-S
= thermal resistance from junction to solder point
[°C/W]
3. Application precautions
a. Drive current of the LED must not exceed the
maximum allowable limit across temperature as
stated in the datasheet. Constant current driving is
recommended to ensure consistent performance.
b. LED is not intended for reverse bias. Do use other
appropriate components for such purpose. When
driving the LED in matrix form, it is crucial to ensure
that the reverse bias voltage is not exceeding the
allowable limit of the LED.
c. Do not use the LED in the vicinity of material with
sulfur content, in environment of high gaseous
sulfur compound and corrosive elements. Examples
of material that may contain sulfur are rubber gasket,
RTV (room temperature vulcanizing) silicone rubber,
rubber gloves etc. Prolonged exposure to such
environment may aect the optical characteristics
and product life.
d. Avoid rapid change in ambient temperature
especially in high humidity environment as this will
cause condensation on the LED.
e. Although the LED is rated as IPx6 and IPx8
according to IEC60529: Degree of protection
provided by enclosure, the test condition may not
represent actual exposure during application. If
the LED is intended to be used in outdoor or harsh
environment, the LED must be protected against
damages caused by rain water, water,dust, oil,
corrosive gases, external mechanical stress etc.
4. Thermal management
Optical, electrical and reliability characteristics of LED
are aected by temperature. The junction temperature
(T
J
) of the LED must be kept below allowable limit at all
times. T
J
can be calculated as below:
T
J
= T
A
+ R
qJ-A
x I
F
x V
Fmax
where;
T
A
= ambient temperature [°C]
R
qJ-A
= thermal resistance from LED junction to ambi-
ent [°C/W]
I
F
= forward current [A]
V
Fmax
= maximum forward voltage [V]
Ts point - pin 5
