LTL17KSL5D Yellow LED Lamp Datasheet - 5mm Diameter - 2.0V Forward Voltage - 75mW Power Dissipation - English Technical Document

1. Product Overview

The LTL17KSL5D is a high-efficiency, yellow diffused through-hole LED lamp designed for a wide range of status indication and illumination applications. It is offered in a standard 5mm cylindrical package, providing a reliable and cost-effective solution for electronic designs requiring clear visual feedback.

1.1 Core Advantages

• High Luminous Intensity: Delivers typical luminous intensity of 400 mcd at 20mA, ensuring excellent visibility.
• Low Power Consumption: Operates with a typical forward voltage of 2.0V, contributing to energy-efficient designs.
• Environmental Compliance: This product is lead (Pb) free and fully compliant with RoHS directives.
• Design Flexibility: Available in a standard 5mm through-hole package, suitable for versatile mounting on printed circuit boards (PCBs) or panels.
• Wide Viewing Angle: Features a typical 50-degree viewing angle (2θ1/2) for broad light distribution.

1.2 Target Applications

This LED is suitable for status indication and backlighting across multiple industries, including:

• Communication equipment
• Computer peripherals and motherboards
• Consumer electronics
• Home appliances
• Industrial control panels and machinery

2. In-Depth Technical Parameter Analysis

2.1 Absolute Maximum Ratings

The following 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. Exceeding this limit can lead to overheating and reduced lifespan.
• DC Forward Current (IF): 30 mA continuous. A peak forward current of 90 mA is permissible under pulsed conditions (duty cycle ≤ 1/10, pulse width ≤ 10μs).
• Operating Temperature Range (Topr): -40°C to +85°C. The device is designed to function reliably within this ambient temperature range.
• Storage Temperature Range (Tstg): -40°C to +100°C.
• Lead Soldering Temperature: 260°C for a maximum of 5 seconds, measured 2.0mm (0.079\") from the LED body.

2.2 Electrical and Optical Characteristics

These parameters are measured at an ambient temperature (TA) of 25°C and define the typical performance of the device.

• Luminous Intensity (Iv): Ranges from a minimum of 180 mcd to a maximum of 880 mcd, with a typical value of 400 mcd at a forward current (IF) of 20mA. The actual intensity is binned (see Section 3).
• Forward Voltage (VF): Typically 2.0V, with a maximum of 2.4V at IF=20mA. This low voltage drop is key for low-power operation.
• Peak Emission Wavelength (λp): Approximately 588 nm, defining the color point of the yellow light.
• Dominant Wavelength (λd): Ranges from 584 nm to 596 nm, categorized into specific bins for color consistency.
• Viewing Angle (2θ1/2): 50 degrees typical. This is the full angle at which the luminous intensity is half the value measured on the central axis.
• Reverse Current (IR): Maximum of 100 μA at a reverse voltage (VR) of 5V. Important: This LED is not designed for reverse bias operation; this parameter is for test purposes only.

3. Binning System Specification

To ensure consistency in brightness and color for production applications, the LTL17KSL5D is classified into bins based on luminous intensity and dominant wavelength.

3.1 Luminous Intensity Binning

Intensity is measured at IF=20mA. Each bin has a tolerance of ±15% on its limits.

• Bin HJ: 180 mcd (Min) to 310 mcd (Max)
• Bin KL: 310 mcd (Min) to 520 mcd (Max)
• Bin MN: 520 mcd (Min) to 880 mcd (Max)

3.2 Dominant Wavelength Binning

Wavelength is measured at IF=20mA. Each bin has a tolerance of ±1 nm on its limits.

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

4. Mechanical and Packaging Information

4.1 Outline Dimensions

The device conforms to a standard 5mm round through-hole LED package. Key dimensional notes include:

• All dimensions are in millimeters (inches provided for reference).
• Standard tolerance is ±0.25mm (0.010\") unless otherwise specified.
• Maximum resin protrusion under the flange is 1.0mm (0.04\").
• Lead spacing is measured at the point where the leads exit the package body.

4.2 Packaging Specifications

The LEDs are supplied in anti-static packaging to prevent damage.

• Unit Pack: Available in quantities of 1000, 500, 200, or 100 pieces per packing bag.
• Inner Carton: Contains 10 packing bags, totaling 10,000 pieces.
• Outer Carton (Shipping Box): Contains 8 inner cartons, totaling 80,000 pieces. The last pack in a shipping lot may not be a full pack.

5. Application and Handling Guidelines

5.1 Recommended Drive Circuit

LEDs are current-driven devices. To ensure uniform brightness, especially when connecting multiple LEDs in parallel, it is strongly recommended to use a current-limiting resistor in series with each LED. Driving LEDs directly from a voltage source without current regulation (connecting multiple LEDs in parallel to a single resistor) can result in significant brightness variations due to minor differences in the forward voltage (Vf) characteristics of individual LEDs.

5.2 Soldering Instructions

Proper soldering is critical to prevent damage to the LED epoxy lens and internal structure.

• Clearance: Maintain a minimum distance of 2mm between the base of the LED lens and the solder point.
• Iron Soldering: Maximum temperature 350°C for a maximum of 3 seconds. Solder only once.
• Wave Soldering: Pre-heat to a maximum of 100°C for up to 60 seconds. Solder wave temperature should not exceed 260°C for a maximum of 5 seconds. Ensure the LED is positioned so the solder does not come within 2mm of the lens base.
• Important: Do not use IR reflow soldering processes for this through-hole LED. Excessive heat or time can cause lens deformation or catastrophic failure.

5.3 Lead Forming and Assembly

• Bend the leads at a point at least 3mm away from the base of the LED lens.
• Do not use the LED body or lead frame as a fulcrum during bending.
• Always perform lead forming before soldering and at room temperature.
• During PCB assembly, apply the minimum clinch force necessary to avoid imposing excessive mechanical stress on the LED leads and body.

5.4 Electrostatic Discharge (ESD) Protection

This LED is susceptible to damage from electrostatic discharge. Implement the following precautions in handling and assembly areas:

• Personnel should wear grounded wrist straps or anti-static gloves.
• All equipment, workbenches, and storage racks must be properly grounded.
• Use ionizers to neutralize static charges that may accumulate on the plastic lens.
• Maintain a formal ESD control program with training and certified work areas.

5.5 Storage and Cleaning

• Storage: For long-term storage outside the original packaging, store in a sealed container with desiccant or in a nitrogen ambient. Recommended storage conditions are ≤30°C and ≤70% relative humidity. LEDs removed from original packaging should be used within three months.
• Cleaning: If necessary, clean only with alcohol-based solvents such as isopropyl alcohol. Avoid harsh chemicals.

6. Performance Curve Analysis

While specific graphical curves are referenced in the datasheet, the following typical behaviors can be inferred from the provided parameters:

6.1 Forward Current vs. Forward Voltage (I-V Curve)

The LED exhibits a non-linear I-V characteristic typical of a diode. The forward voltage (Vf) has a specified range (2.0V to 2.4V typ/max at 20mA). As current increases, Vf will increase slightly. This characteristic underscores the importance of current-limiting resistors for stable operation.

6.2 Luminous Intensity vs. Forward Current

The luminous intensity (Iv) is approximately proportional to the forward current (If) within the device's operating range. Operating above the absolute maximum DC current (30mA) will not yield proportional increases in light output and will significantly increase power dissipation and junction temperature, reducing efficiency and lifespan.

6.3 Temperature Dependence

Like all LEDs, the performance of the LTL17KSL5D is temperature-dependent. As the junction temperature increases, the forward voltage typically decreases slightly, while the luminous intensity will decrease. The wide operating temperature range (-40°C to +85°C) ensures functionality in various environments, but designers should account for potential intensity variation at temperature extremes.

7. Design Considerations and FAQs

7.1 How do I select the correct current-limiting resistor?

Use Ohm's Law: R = (Vsupply - Vf_LED) / If. For example, with a 5V supply, a typical Vf of 2.0V, and a desired If of 20mA: R = (5V - 2.0V) / 0.020A = 150 Ω. Always use the maximum Vf from the datasheet (2.4V) for a conservative design to ensure the current does not exceed the desired value: R_min = (5V - 2.4V) / 0.020A = 130 Ω. A standard 150 Ω resistor would be a suitable choice, providing between 17.3mA and 20mA depending on the actual Vf of the LED.

7.2 Can I drive this LED without a resistor?

No. Connecting an LED directly to a voltage source is not recommended as it attempts to draw current limited only by its internal resistance and the source, which can easily exceed the maximum ratings and destroy the device instantly.

7.3 What is the difference between peak wavelength and dominant wavelength?

Peak Wavelength (λp) is the single wavelength at which the spectral power distribution of the emitted light is maximum. Dominant Wavelength (λd) is a calculated value derived from the CIE chromaticity diagram that represents the perceived color of the light as a single wavelength. For monochromatic LEDs like this yellow one, λp and λd are often close but not identical. λd is more relevant for color specification in applications.

7.4 How does the viewing angle affect my application?

A 50-degree viewing angle provides a broad, diffuse light pattern. This is ideal for status indicators that need to be visible from a wide range of viewing positions. For applications requiring a more focused beam, a lens with a narrower viewing angle would be more appropriate.

8. Technical Comparison and Positioning

The LTL17KSL5D positions itself as a general-purpose, high-reliability yellow indicator LED. Its key differentiators include a well-defined binning structure for brightness and color consistency, comprehensive maximum ratings that ensure robust operation, and detailed application cautions covering ESD, soldering, and handling. Compared to non-binned or lower-specification LEDs, it offers designers greater predictability in mass production, reducing the risk of visual inconsistency in finished products. The through-hole package ensures ease of prototyping and compatibility with a vast range of existing PCB designs, making it a versatile choice for both new designs and legacy product maintenance.