SMD LED LTST-C990NEKT-ID Datasheet - Red 620-625nm - 20mA - 1.6-2.4V - English Technical Document

1. Product Overview

This document details the specifications for a high-performance, surface-mount LED designed for automated assembly processes. The device utilizes an Ultra Bright AlInGaP chip to deliver superior luminous output in a compact, dome-lens package. Its primary design goals are reliability, compatibility with modern manufacturing techniques, and suitability for space-constrained applications.

1.1 Features

• Compliant with RoHS environmental directives.
• Features a dome lens for optimized light distribution.
• Built with an Ultra Bright AlInGaP semiconductor chip.
• Supplied in tape-and-reel packaging (8mm tape on 7\" reels) for automated pick-and-place.
• Conforms to EIA standard package outlines.
• Designed for direct interface with integrated circuits (I.C. compatible).
• Fully compatible with automatic placement equipment.
• Withstands standard infrared (IR) reflow soldering processes.

1.2 Applications

This LED is engineered for a broad spectrum of electronic equipment, including but not limited to:

• Telecommunication devices and office automation equipment.
• Home appliances and industrial control systems.
• Backlighting for keypads and keyboards.
• Status and power indicators.
• Micro-displays and symbol illumination.

2. Package Dimensions and Mechanical Information

The LED is housed in a standard surface-mount package. Critical dimensions are provided in the datasheet drawings, with all measurements in millimeters. The standard tolerance for unspecified dimensions is \u00b10.1 mm. The lens is water clear, while the light source emits a red color. Precise mechanical drawings are essential for PCB footprint design to ensure proper soldering and alignment.

3. Ratings and Characteristics

All specifications are defined at an ambient temperature (Ta) of 25\u00b0C unless otherwise stated. Exceeding Absolute Maximum Ratings may cause permanent damage.

3.1 Absolute Maximum Ratings

• Power Dissipation (Pd): 62.5 mW
• Peak Forward Current (I_F): 60 mA (at 1/10 duty cycle, 0.1ms pulse width)
• Continuous Forward Current (I_F): 25 mA DC
• Reverse Voltage (V_R): 5 V
• Operating Temperature Range: -30\u00b0C to +85\u00b0C
• Storage Temperature Range: -40\u00b0C to +85\u00b0C
• Infrared Reflow Soldering Condition: 260\u00b0C peak temperature for 10 seconds maximum.

3.2 Electrical and Optical Characteristics

Typical performance parameters measured under standard test conditions (I_F = 20mA, Ta=25\u00b0C).

• Luminous Intensity (I_V): 1155.0 - 2145.0 mcd (millicandela). Measured with a filter approximating the CIE photopic eye response.
• Viewing Angle (2\u03b8_1/2): 75 degrees. Defined as the full angle where intensity drops to half its axial value.
• Peak Emission Wavelength (\u03bb_P): Typically 632 nm.
• Dominant Wavelength (\u03bb_d): 620.0 - 625.0 nm. The single wavelength perceived as the color of the LED.
• Spectral Line Half-Width (\u0394\u03bb): Typically 20 nm. The spectral bandwidth at half the peak intensity.
• Forward Voltage (V_F): 1.6 - 2.4 V at 20mA.
• Reverse Current (I_R): 10 \u03bcA maximum at V_R = 5V.

4. Binning System

To ensure color and brightness consistency in production, LEDs are sorted into bins based on luminous intensity.

4.1 Luminous Intensity Bin Codes

• Bin W1: 1155.0 mcd (Min) to 1400.0 mcd (Max)
• Bin W2: 1400.0 mcd (Min) to 1800.0 mcd (Max)
• Bin X1: 1800.0 mcd (Min) to 2145.0 mcd (Max)

Tolerance within each bin is \u00b115%. Designers should specify the required bin code for applications demanding tight brightness matching.

5. Performance Curve Analysis

The datasheet includes typical characteristic curves which are crucial for understanding device behavior under non-standard conditions. These typically include:

• Forward Current vs. Forward Voltage (I-V Curve): Shows the nonlinear relationship, important for driver design.
• Luminous Intensity vs. Forward Current: Demonstrates how light output scales with drive current.
• Luminous Intensity vs. Ambient Temperature: Shows the derating of light output as temperature increases, a critical factor for thermal management.
• Spectral Distribution: Illustrates the relative power emitted across wavelengths, centered around the dominant wavelength.

Analyzing these curves allows designers to optimize drive conditions, manage thermal effects, and predict performance in the final application.

6. Assembly and Handling Guide

6.1 Recommended PCB Pad Layout

A suggested land pattern (footprint) is provided to ensure reliable solder joint formation, proper alignment, and sufficient mechanical strength. Adhering to this design minimizes tombstoning and other placement defects.

6.2 Soldering Guidelines

The device is qualified for lead-free (Pb-free) infrared reflow soldering processes. A sample JEDEC-compliant temperature profile is recommended:

• Pre-heat: 150-200\u00b0C
• Pre-heat Time: Maximum 120 seconds.
• Peak Temperature: Maximum 260\u00b0C.
• Time Above 260\u00b0C: Maximum 10 seconds.
• Number of Reflow Passes: Maximum two times.

For hand soldering with an iron, the tip temperature should not exceed 300\u00b0C, with contact time limited to 3 seconds for a single operation only. The actual profile must be characterized for the specific PCB assembly, considering board thickness, component density, and solder paste specifications.

6.3 Cleaning

If cleaning is necessary after soldering, only specified solvents should be used. Immersing the LED in ethyl alcohol or isopropyl alcohol at room temperature for less than one minute is acceptable. Unspecified chemicals may damage the epoxy package or lens.

6.4 Electrostatic Discharge (ESD) Precautions

LEDs are sensitive to electrostatic discharge and voltage surges. Proper ESD controls must be implemented during handling and assembly. This includes the use of grounded wrist straps, anti-static mats, and ensuring all equipment is properly grounded.

7. Storage and Moisture Sensitivity

The LEDs are packaged in moisture-barrier bags with desiccant to maintain a dry environment.

• Sealed Package: Store at \u2264 30\u00b0C and \u2264 90% Relative Humidity. Shelf life is one year from the bag seal date.
• Opened Package: For components removed from the sealed bag, the storage ambient should not exceed 30\u00b0C / 60% RH. Components should be reflowed within one week (MSL Level 3).
• Extended Storage (Out of Bag): Store in a sealed container with desiccant or in a nitrogen desiccator.
• Rebaking: If LEDs are exposed to ambient air for more than one week, they must be baked at approximately 60\u00b0C for at least 20 hours prior to reflow soldering to remove absorbed moisture and prevent \"popcorning\" damage.

8. Packaging Specifications

The components are supplied on embossed carrier tape for automated handling.

• Tape Width: 8 mm.
• Reel Diameter: 7 inches.
• Quantity per Reel: 3000 pieces.
• Minimum Order Quantity (MOQ): 500 pieces for remainder quantities.
• Pocket Coverage: Empty pockets are sealed with cover tape.
• Missing Components: A maximum of two consecutive missing LEDs is allowed per reel specification.
• Standard: Packaging conforms to ANSI/EIA-481 specifications.

9. Application Design Considerations

9.1 Drive Circuit Design

LEDs are current-operated devices. To ensure uniform brightness and prevent current hogging, each LED in a parallel configuration must have its own current-limiting resistor. The series resistor value (R_s) can be calculated using Ohm's Law: R_s = (V_supply - V_F) / I_F, where V_F is the forward voltage of the LED at the desired current I_F. Using the typical V_F for calculation is advised, but design margins should account for the min/max range.

9.2 Thermal Management

While the package is small, effective thermal management is essential for maintaining performance and longevity. Exceeding the maximum junction temperature can lead to accelerated lumen depreciation and reduced lifespan. Design practices include ensuring adequate copper area on the PCB under and around the LED pads to act as a heat sink, and avoiding operation at absolute maximum current in high ambient temperatures.

9.3 Optical Design

The 75-degree viewing angle provides a broad emission pattern. For applications requiring focused or collimated light, secondary optics (lenses, light guides) will be necessary. The water-clear dome lens is suitable for applications where the native LED color is desired without diffusion.

10. Reliability and Application Scope

These LEDs are intended for use in standard commercial and industrial electronic equipment. For applications requiring exceptional reliability where failure could jeopardize safety or health (e.g., aviation, medical life-support, transportation safety systems), additional qualification and consultation with the component manufacturer are mandatory. The specifications and guidelines provided form the basis for reliable integration into standard electronic assemblies.