ASMB-UTF2-0E20B datasheet(10/12 Pages) BOARDCOM

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ASMB-UTF2-0E20B Data Sheet

2828 Tricolor PLCC-6 LED

Broadcom

ASMB-UTF2-0E20B-DS101



Baking is required if:

– The HIC indicator indicates a change in color for

10% and 5%, as stated on the HIC.

– The LEDs are exposed to conditions of >30°C/60%

RH at any time.

– The LED's floor life exceeded 24 hours.

The recommended baking condition is: 65°C ±5ºC for

24 hours.

Baking can only be done once.



Storage:

The soldering terminals of these Broadcom LEDs are

silver plated. If the LEDs are exposed in ambient

environments for too long, the silver plating might be

oxidized, thus affecting its solderability performance. As

such, keep unused LEDs in a sealed MBB with

desiccant or in a desiccator at <5% RH.

Application Precautions



The drive current of the LED must not exceed the

maximum allowable limit across temperature as stated

in the data sheet. Constant current driving is

recommended to ensure consistent performance.



Circuit design must cater to the whole range of forward

voltage (VF) of the LEDs to ensure the intended drive

current can always be achieved.



The LED exhibits slightly different characteristics at

different drive currents, which may result in a larger

variation of performance (meaning: intensity,

wavelength, and forward voltage). Set the application

current as close as possible to the test current to

minimize these variations.



The LED is not intended for reverse bias. Use other

appropriate components for such purposes. When

driving the LED in matrix form, ensure that the reverse

bias voltage does not exceed the allowable limit of the

LED.



As actual application might not be exactly similar to the

test conditions, do verify that the LED will not be

damaged by prolonged exposure in the intended

environment.



Avoid rapid changes in ambient temperature, especially

in high-humidity environments, because they cause

condensation on the LED.



If the LED is intended to be used in harsh or outdoor

environments, protect the LED against damages

caused by rain water, water, dust, oil, corrosive gases,

external mechanical stresses, and so on.

Thermal Management

The optical, electrical, and reliability characteristics of the

LED are affected by temperature. Keep the junction

temperature (TJ) of the LED below the allowable limit at all

times. TJ can be calculated as follows:

TJ = TA + RθJ-A × IF × VFmax

where:

TA = ambient temperature (°C)

RθJ-A = thermal resistance from LED junction to ambient

(°C/W)

IF = forward current (A)

VFmax = maximum forward voltage (V)

The complication of using this formula lies in TA and RθJ-A.

Actual TA is sometimes subjective and hard to determine.

RθJ-A varies from system to system depending on design

and is usually not known.

Another way of calculating TJ is by using the solder point

temperature, TS as follows:

TJ = TS + RθJ-S × IF × VFmax

where:

TS = LED solder point temperature as shown in the

following figure (°C)

RθJ-S = thermal resistance from junction to solder point

(°C/W)

IF = forward current (A)

VFmax = maximum forward voltage (V)

Figure 17: Solder Point Temperature on PCB

TS can be easily measured by mounting a thermocouple on

the solder joint as shown in preceding figure, while RθJ-S is

provided in the data sheet. Verify the TS of the LED in the

final product to ensure that the LEDs are operating within all

maximum ratings stated in the data sheet.

ASMB-UTF2-0E20B Datasheet(PDF) 10 Page - Broadcom Corporation.

ASMB-UTF2-0E20B Datasheet(HTML) 10 Page - Broadcom Corporation.

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