HDSP-Ax11/-Ax13 Series, HDSP-Fx11/-Fx13 Series, HDSP-Hx11/-Hx13 Series,
HDSP-Kx11/-Kx13 Series Data Sheet Black Surface Seven-Segment Displays
Broadcom AV02-2555EN
13
Precautionary Notes
Soldering and Handling Precautions
Set and maintain the wave soldering parameters
according to the recommended temperature and dwell
time. Perform daily checks on the profile to ensure that
it is always conforming to the recommended conditions.
Exceeding these conditions will over-stress the LEDs
and cause premature failures.
Use only bottom preheaters to reduce thermal stress
experienced by the LEDs.
Recalibrate the soldering profile before loading a new
type of a PCB. PCBs with different sizes and designs
(component density) will have different heat capacities
and might cause a change in temperature experienced
by the PCB if the same wave soldering setting is used.
Do not perform wave soldering more than once.
Any alignment fixture used during wave soldering must
be loosely fitted and must not apply stress on the LEDs.
Use non-metal material because it will absorb less heat
during the wave soldering process.
At elevated temperatures, the LEDs are more
susceptible to mechanical stress. Allow the PCB to be
sufficiently cooled to room temperature before handling.
Do not apply stress to the LED when it is hot.
Use wave soldering to solder the LED. Use hand
soldering only for rework or touch up if unavoidable, but
it must be strictly controlled to following conditions:
– Soldering iron tip temperature = 315°C maximum.
– Soldering duration = 2 seconds maximum.
– Number of cycles = 1 only.
– Power of soldering iron = 50W maximum.
For ESD-sensitive devices, apply proper ESD
precautions at the soldering station. Use only an
ESD-safe soldering iron.
Do not touch the LED package body with the soldering
iron except for the soldering terminals because it may
cause damage to the LED.
Confirm beforehand whether the functionality and
performance of the LED is affected by soldering with
hand soldering.
Keep the heat source at least 1.6 mm away from the
LED body during soldering.
Design an appropriate hole size to avoid problems
during insertion.
Cleaning agents from the ketone family (acetone,
methyl ethylketone, and so on) and from the chlorinated
hydrocarbon family (methylene chloride,
trichloroethylene, carbon tetrachloride, and so on) are
not recommended for cleaning the LED displays. All of
these various solvents attack or dissolve the
encapsulating epoxies used to form the package of
plastic LED parts.
For the purpose of cleaning, wash with DI water only.
The cleaning process should take place at room
temperature only. Clear any water or moisture from the
LED display immediately after washing.
Use of No clean solder paste is recommended for
soldering.
Figure 21: Recommended Wave Soldering Profile
NOTE: Figure 21 refers to measurements with
thermocouple mounted at the bottom of the PCB.
Application Precautions
The drive current of the LED must not exceed the
maximum allowable limit across temperatures 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 (V
F
) 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 (such as 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.