Absolute Maximum Rating
Never exceed the absolute maximum rating specified in datasheets and catalogs, even momentarily. In particular, the following points should be noted:
During LED operation, elements may be damaged by the current spike generated when the power switch is turned on and off, or when the output is adjusted. Before use, be sure to check the transient characteristics of the power supply and to make sure that the current spike does not exceed the absolute maximum rating of the forward current
If the LED element is driven beyond the absolute maximum rating of the forward current, the reliability of the element will degrade significantly. Also, when driving the LED in pulses, make sure the pulse current does not exceed the maximum permissible pulse current value specified in the datasheet section titled “Forward Current – Pulse Duration”
Tj vs. Rthjs
There is a relationship between junction temperature (Tj) and thermal resistance (Rthjs); therefore, care should be taken to ensure that the junction temperature does not exceed the absolute maximum rating as follows:
Tj = Rthjs x Pd + Ts
The indicators above follow the following conventions:
Tj: Junction temperature; Rthjs: Thermal Resistance; Ts: Temperature of solder point
Pd = VfxIf; Vf: Forward voltage; If: Forward current; Po: Radiant Energy
The absolute maximum ratings are specified at a case temperature (at the solder point) of 25°C. Therefore, the higher the temperature, the higher the maximum rating. Therefore, as the temperature increases, the maximum forward current and allowable loss decreases and the operating range is limited, so design considerations much include as much leeway as possible
Never apply a reverse voltage that exceeds the absolute maximum rating
The LED elements may be damaged or deteriorated by static electricity; therefore, take the following precautions when using the LEDs. Electrostatic breakdowns are caused by static electricity charged on the human body, abnormal pulses generated by the testing equipment, leakage voltage of the soldering iron, and improper materials of the carrier.
To prevent damage due to static electricity charged on the body’s clothing, ground the body through a high resistance (usually 500 kΩ to 1 MΩ) to discharge static electricity while handling the soldering iron.
Ground the soldering iron to prevent leaked voltage from the soldering iron being applied to the device.
Use containers and jigs that will not be electrically charged due to vibration during transportation. It is effective to use a conductive container or aluminum foil.
SMD type LEDs
The SMD (surface-mounted device) type LED products are packed in cut tape, tape & reel, or a tray according to the specifications for that particular model of LED. Also in the packaging, you will find a silica gel indicator or indicator card and silica gel. This is all placed in a moisture proof bag and thermally sealed.
Mold type LEDs
The mold type LEDs are packed in batches of 500 pieces in plastic bags, or anti-static bags if necessary, which are then heat sealed. In case of taping, LEDs are shipped in inner boxes in batches of 2,500 pieces for diameters of 5 mm, or 4,000 pieces for diameters of 3 mm.
SMD type LEDs
- SMD type LED products are equivalent to MSL4, unless otherwise specified. If the SMD type product absorbs moisture, the moisture may expand due to heat during reflow, etc., causing de-lamination at the interface inside the package. This may result in failure.
- The silica gel indicator and the indicator card included in the moisture-proof bag will change color from blue to red when it absorbs moisture.
- If the moisture-proof bag is unopened, store the product in an environment of 30°C or less and 60% humidity or less, with a maximum storage period of 12 months.
- After opening the moisture-proof bag, the LEDs must be mounted within 72 hours in an environment of 30°C or less and 50% humidity or less.
If there are any unused LEDs remaining, place them in a moisture-proof bag together with silica gel and store them in a sealed container.
Please note: the 72 hour time limit does not include the time the LEDs are stored in an airtight bag with silica gel after opening the bag.
- After the storage period has expired, bake the product once at most. If the indicator turns red within the storage period, baking treatment should be performed no more than once.
For the baking process, we recommend removing the device from the embossed carrier tape and baking it in an oven at 100°C for 24 hours.
Mold type LEDs
For mold type LEDs, store them at a temperature of 30°C or less and humidity of 70% RH or less, and keep them in the same location for up to one year.
The LEDs should not be stored in an environment where they are exposed to corrosive gases, etc., which may cause deterioration of the leads.
SMBB LEDs (-02, -03 and -05 lens types)
- Be careful not to overload the product when handling it with tweezers.
- Do not hold the lens directly with tweezers. Doing so may result in damage to the lens or non-lighting due to wire breakage or separation.
- Be careful not to drop the product. If the product is deformed, foreign matter may adhere to the lens or cause it to become dirty, etc.
- When wiping out stains on the lens, use a cloth with isopropyl alcohol to prevent excessive force from being applied to the lens.
- It is recommended to use an automatic mounting machine during the mounting of this product type.
Mold Type LED Soldering Condition (Plastic Mold)
Recommended Hand-Soldering Condition
Hand-soldering must not be performed more than once. The temperature must not exceed 350°C, for a duration exceeding no more than a maximum of 3 seconds.
Recommended Flow Soldering Profile
Soldering Conditions for SMD (Surface Mount Device) LEDs
SMD Type LED is designed to be reflow soldered to a printed circuit board (PCB)
Reflow soldering must not be performed more than once.
When soldering, do not apply stress to the LED while the LED is hot
Hand-soldering is not recommended for SMD Type LEDs
Recommended Flow Soldering Profile
If you would like further advice or technical guidance regarding Ushio Epitex SWIR LEDs, contact Ushio’s regional experts via the following link:
Don’t get left behind!
Looking to stay up-to-date with the latest breakthroughs, product releases, and features hitting the market? Join the SWIR-LED Club for FREE and get Ushio Epitex news deliver your mailbox.