T-1 Yellow Diffused LED LTL17KSL6D Datasheet - Dimensions 5.4x3.8mm - Voltage 2.4V - Power 75mW - English Technical Document

1. Product Overview

The LTL17KSL6D is a high-efficiency, low-power consumption LED designed for through-hole mounting on printed circuit boards (PCBs) or panels. It features a popular T-1 (5mm) diameter package with a diffused yellow lens, providing a wide and uniform viewing angle. The device utilizes AlInGaP (Aluminum Indium Gallium Phosphide) technology as the light source, which is known for its high luminous efficiency and stability. This LED is RoHS compliant, meaning it is manufactured without the use of hazardous substances like lead (Pb), making it suitable for modern electronic applications with environmental regulations.

Its core advantages include a high typical luminous intensity output of 520 millicandelas (mcd) at a standard drive current of 20mA, coupled with a relatively low forward voltage. This combination results in excellent energy efficiency. The device is also I.C. (Integrated Circuit) compatible due to its low current requirement, allowing for easy integration into various digital and analog control circuits without the need for complex driver stages.

2. Technical Parameters Deep Objective Interpretation

2.1 Absolute Maximum Ratings

These ratings define the limits beyond which permanent damage to the device may occur. Operation under these conditions is not guaranteed.

• Power Dissipation (Pd): 75 mW maximum. This is the total power the LED package can safely dissipate as heat. Exceeding this limit risks thermal damage.
• Continuous Forward Current (IF): 30 mA maximum under DC conditions. This is the safe upper limit for constant operation.
• Peak Forward Current: 60 mA maximum, but only under pulsed conditions (1/10 duty cycle, 0.1ms pulse width). This allows for brief over-driving for applications requiring higher instantaneous brightness, like indicators or strobes.
• Derating: The maximum continuous forward current must be linearly reduced by 0.66 mA for every degree Celsius the ambient temperature (TA) rises above 50°C. This is crucial for thermal management in high-temperature environments.
• Reverse Voltage (VR): 5 V maximum. LEDs are not designed to withstand significant reverse bias. Exceeding this voltage can cause immediate junction breakdown.
• Operating & Storage Temperature: The device is rated for operation from -40°C to +80°C and can be stored from -55°C to +100°C.
• Lead Soldering Temperature: 260°C for a maximum of 5 seconds, measured 2.0mm from the LED body. This defines the process window for hand or wave soldering.

2.2 Electrical & Optical Characteristics

These are the typical performance parameters measured at an ambient temperature of 25°C.

• Luminous Intensity (Iv): Ranges from a minimum of 400 mcd to a typical value of 520 mcd at IF=20mA. This is the perceived brightness of the LED as measured by a sensor filtered to match the human eye's photopic response (CIE curve).
• Viewing Angle (2θ1/2): Typically 60 degrees (55° minimum). This is the full angle at which the luminous intensity drops to half of its value measured on the central axis. The diffused lens creates this wide viewing angle.
• Peak Emission Wavelength (λP): Typically 588 nm. This is the wavelength at which the spectral power output is highest.
• Dominant Wavelength (λd): Ranges from 584 nm to 596 nm, with a typical value of 587 nm. This is the single wavelength that best represents the perceived color of the LED, derived from the CIE chromaticity diagram. It is the key parameter for color specification.
• Spectral Line Half-Width (Δλ): Typically 15 nm. This indicates the spectral purity or bandwidth of the emitted yellow light.
• Forward Voltage (VF): Typically 2.0V, with a maximum of 2.4V at IF=20mA. This is the voltage drop across the LED when conducting current.
• Reverse Current (IR): Maximum of 100 μA at VR=5V. This is the small leakage current when the LED is reverse-biased within its maximum rating.
• Capacitance (C): Typically 40 pF measured at zero bias and 1MHz. This is the junction capacitance, relevant for high-frequency switching applications.

3. Bin Table Specification

The product is sorted into bins based on key performance parameters to ensure consistency within a production batch or for specific application needs.

3.1 Luminous Intensity Binning

Unit: mcd @ 20mA. Tolerance for each bin limit is ±15%.

• Bin Code L: Minimum 400 mcd, Maximum 520 mcd.
• Bin Code M: Minimum 520 mcd, Maximum 680 mcd.
• Bin Code N: Minimum 680 mcd, Maximum 880 mcd.

The LTL17KSL6D part number corresponds to Bin L for luminous intensity (400-520 mcd typical).

3.2 Dominant Wavelength Binning

Unit: nm @ 20mA. Tolerance for each bin limit is ±1 nm.

• Bin Code H15: 584.0 nm to 586.0 nm
• Bin Code H16: 586.0 nm to 588.0 nm
• Bin Code H17: 588.0 nm to 590.0 nm
• Bin Code H18: 590.0 nm to 592.0 nm
• Bin Code H19: 592.0 nm to 594.0 nm
• Bin Code H20: 594.0 nm to 596.0 nm

The specific bin for a given unit within the 584-596 nm range would be marked or specified separately.

4. Mechanical & Package Information

4.1 Package Dimensions

The LED conforms to the standard T-1 (5mm) through-hole package profile. Key dimensions include:

• Overall length from lens tip to lead end: Approximately 25.0 mm (0.984 inches) minimum.
• Lens diameter: 5.4 mm (0.212 inches) nominal.
• Body/flange diameter: 3.8 mm (0.15 inches) maximum.
• Lead spacing: 2.54 mm (0.1 inches) nominal, measured where leads emerge from the package.
• Lead diameter: 0.5 mm ± 0.05 mm (0.0197" ± 0.002").
• A minimum bend radius point of 1.6mm from the base of the lens is required during lead forming.

The cathode is typically identified by a flat spot on the lens rim or a shorter lead, depending on the manufacturer's standard (refer to the specific drawing for the LTL17KSL6D).

5. Soldering & Assembly Guidelines

5.1 Storage Conditions

LEDs should be stored in an environment not exceeding 30°C and 70% relative humidity. If removed from their original moisture-barrier packaging, they should be used within three months. For longer storage outside the original pack, use a sealed container with desiccant or a nitrogen ambient.

5.2 Cleaning

If cleaning is necessary, use alcohol-based solvents like isopropyl alcohol. Avoid harsh or unknown chemical cleaners.

5.3 Lead Forming & Placement

• Bend leads at a point at least 1.6mm from the base of the LED lens.
• Do not use the LED body as a fulcrum for bending.
• Perform all lead forming at room temperature and before the soldering process.
• During PCB insertion, apply minimal clinching force to avoid mechanical stress on the epoxy seal.

5.4 Soldering Process

For through-hole LEDs, wave soldering or hand soldering is applicable. Infrared (IR) reflow is not suitable.

• Hand Soldering: Iron temperature maximum 400°C. Contact time maximum 3 seconds per lead. Perform only once.
• Wave Soldering: Preheat temperature maximum 120°C for up to 60 seconds. Solder wave temperature maximum 260°C. Contact time with solder maximum 5 seconds.
• Critical Clearance: Maintain a minimum distance of 1.6mm (or 2.0mm as noted in some sections) from the base of the LED lens to the solder point on the lead. This prevents epoxy resin from climbing up the lead due to capillary action during soldering, which can cause soldering defects or stress cracks.
• Avoid dipping the lens itself into the solder.
• Do not apply stress to the leads while the LED is hot from soldering.

6. Application Suggestions & Design Considerations

6.1 Drive Circuit Design

LEDs are current-operated devices. Their brightness is primarily a function of forward current (IF), not voltage. To ensure uniform brightness when driving multiple LEDs, especially in parallel, it is strongly recommended to use a series current-limiting resistor for each LED. The simple circuit consists of a voltage source (Vcc), a resistor (R), and the LED in series. The resistor value is calculated as R = (Vcc - VF) / IF, where VF is the forward voltage of the LED at the desired current IF. Using a common resistor for multiple LEDs in parallel (Circuit Model B in the datasheet) is not recommended due to variations in the I-V characteristics between individual LEDs, which can lead to significant differences in current share and thus brightness.

6.2 Electrostatic Discharge (ESD) Protection

LEDs, like most semiconductor devices, are susceptible to damage from electrostatic discharge. Precautions must be taken during handling and assembly:

• Operators should wear grounded wrist straps or anti-static gloves.
• All equipment, workbenches, and storage racks must be properly grounded.
• Use conductive foam or containers for transport and storage of loose devices.

6.3 Thermal Management

While this is a low-power device, adhering to the power dissipation and current derating specifications is essential for long-term reliability. Ensure adequate airflow if used in enclosed spaces or at high ambient temperatures. The derating factor of 0.66 mA/°C above 50°C must be applied to calculate the maximum allowable continuous current in the actual operating environment.

6.4 Typical Application Scenarios

Given its specifications, the LTL17KSL6D is well-suited for:

• Status and Power Indicators: On consumer electronics, industrial control panels, and instrumentation due to its high brightness and wide viewing angle.
• Backlighting: For small legends, symbols, or panel areas where a diffused yellow glow is required.
• Automotive Interior Indicators: (Assuming qualification for such use) for dashboard or switch illumination.
• General Purpose Signaling: In appliances, toys, and decorative lighting.

7. Packaging & Ordering Information

The standard packaging for the LTL17KSL6D is as follows:

• Basic Pack: 1,000 pieces per anti-static moisture-barrier packing bag.
• Inner Carton: Contains 10 packing bags, totaling 10,000 pieces.
• Outer Shipping Carton: Contains 8 inner cartons, totaling 80,000 pieces.

The part number structure LTL17KSL6D encodes key attributes: likely indicating the series, package (T-1), color (Yellow), lens type (Diffused), and the specific intensity/wavelength bin (L6D). The exact decoding should be confirmed with the manufacturer's part numbering guide.

8. Cautions & Reliability Notes

The device is intended for standard electronic equipment. For applications requiring exceptional reliability where failure could risk safety (e.g., aviation, medical, transportation), specific consultation and qualification are necessary prior to design-in. Always adhere to the Absolute Maximum Ratings and recommended operating conditions. Specifications are subject to change, so always refer to the latest official datasheet for critical design work.