Orange SMD LED LTST-C170KFKT Datasheet - Package Dimensions - Forward Voltage 2.4V - Luminous Intensity 90mcd - English Technical Document

1. Product Overview

This document provides the complete technical specifications for a high-performance, surface-mount Orange LED. The device utilizes an Ultra Bright AlInGaP (Aluminum Indium Gallium Phosphide) chip, which is known for its high luminous efficiency and excellent color purity in the orange-red spectrum. It is designed as a RoHS-compliant green product, ensuring environmental safety. The LED is supplied in industry-standard 8mm tape on 7-inch diameter reels, making it fully compatible with automated pick-and-place assembly equipment used in high-volume electronics manufacturing. Its design is compatible with both infrared (IR) and vapor phase reflow soldering processes, which are standard for modern PCB assembly lines.

2. Technical Parameter Deep-Dive

2.1 Absolute Maximum Ratings

The device's operational limits are defined at an ambient temperature (Ta) of 25\u00b0C. Exceeding these ratings may cause permanent damage. The maximum continuous DC forward current is 30 mA. For pulsed operation, a peak forward current of 80 mA is permissible under a 1/10 duty cycle with a 0.1ms pulse width. The maximum power dissipation is 75 mW. The device can withstand a reverse voltage of up to 5 V. The operating and storage temperature range is specified from -55\u00b0C to +85\u00b0C, indicating suitability for a wide range of environmental conditions. Critical soldering conditions are also defined: wave and infrared soldering at 260\u00b0C for 5 seconds, and vapor phase soldering at 215\u00b0C for 3 minutes.

2.2 Electrical & Optical Characteristics

Key performance parameters are measured at Ta=25\u00b0C and a forward current (IF) of 20 mA. The luminous intensity (Iv) has a typical value of 90.0 millicandelas (mcd) with a minimum of 45.0 mcd. The viewing angle (2\u03b81/2), defined as the full angle at which intensity drops to half its axial value, is 130 degrees, providing a wide emission pattern. The peak emission wavelength (\u03bbP) is typically 611 nm, and the dominant wavelength (\u03bbd) is 605 nm, firmly placing the output in the orange color region. The spectral line half-width (\u0394\u03bb) is 17 nm, indicating a relatively narrow spectral bandwidth. The forward voltage (VF) ranges from 2.0 V to 2.4 V at 20 mA. The reverse current (IR) is a maximum of 100 \u00b5A at VR=5V, and the junction capacitance (C) is typically 40 pF measured at 0V and 1 MHz.

3. Binning System Explanation

The product employs a binning system to categorize units based on luminous intensity. This ensures consistency in brightness for applications requiring uniform illumination. The bin codes and their corresponding intensity ranges at IF=20mA are: Bin P (45.0 - 71.0 mcd), Bin Q (71.0 - 112.0 mcd), Bin R (112.0 - 180.0 mcd), and Bin S (180.0 - 280.0 mcd). A tolerance of +/-15% is applied to each intensity bin. Designers must specify the required bin code when ordering to guarantee the desired brightness level for their application.

4. Performance Curve Analysis

The datasheet references typical performance curves which are essential for understanding device behavior under varying conditions. These curves typically include the relationship between forward current (IF) and forward voltage (VF), showing the diode's characteristic exponential turn-on. The relationship between luminous intensity and forward current is crucial for drive current selection. Curves depicting the variation of luminous intensity and dominant wavelength with ambient temperature are critical for thermal management and color stability analysis in designs exposed to temperature fluctuations. The angular intensity distribution pattern is implied by the viewing angle specification, showing how light is emitted across the 130-degree cone.

5. Mechanical & Packaging Information

5.1 Package Dimensions

The LED conforms to an EIA standard surface-mount package outline. All critical dimensions for PCB footprint design are provided in millimeters, with a general tolerance of \u00b10.10 mm unless otherwise specified. The lens is described as \"Water Clear,\" which is typical for non-diffused, high-intensity LEDs. Detailed mechanical drawings would show the body length, width, height, lead spacing, and lens geometry.

5.2 Soldering Pad Layout & Polarity

A suggested soldering pad dimension layout is provided to ensure reliable solder joint formation and proper alignment during reflow. The pad design accounts for thermal relief and solder fillet formation. The polarity of the LED (anode and cathode) is clearly indicated in the package drawing, typically by a marking on the body or an asymmetric pad design, which is vital for correct PCB assembly.

5.3 Tape and Reel Specifications

The device is packaged in 8mm wide embossed carrier tape wound on 7-inch (178mm) diameter reels. Standard reel quantity is 3000 pieces. Packaging follows ANSI/EIA 481-1-A-1994 specifications. Key tape dimensions include pocket pitch, pocket size, and cover tape specifications. Notes specify that empty pockets are sealed, a minimum packing quantity for remainders is 500 pieces, and the maximum number of consecutive missing components is two.

6. Soldering & Assembly Guidelines

6.1 Recommended Reflow Profiles

Two suggested infrared (IR) reflow soldering profiles are provided: one for standard tin-lead (SnPb) solder process and one for lead-free (Pb-free) solder process, typically using SAC (Sn-Ag-Cu) alloy. The lead-free profile requires a higher peak temperature, around 260\u00b0C, as indicated by the absolute maximum ratings. The profiles define critical parameters: preheat temperature and time, temperature ramp-up rate, time above liquidus (TAL), peak temperature, and cooling rate. Adherence to these profiles is necessary to prevent thermal damage to the LED's plastic package and internal wire bonds.

6.2 Storage Conditions

LEDs should be stored in an environment not exceeding 30\u00b0C and 70% relative humidity. Once removed from their original moisture-barrier packaging, it is recommended to complete the IR reflow soldering process within 672 hours (28 days). For longer storage outside the original bag, LEDs should be kept in a sealed container with desiccant or in a nitrogen-purged desiccator. Components stored beyond 672 hours should be baked at approximately 60\u00b0C for at least 24 hours before soldering to remove absorbed moisture and prevent \"popcorning\" during reflow.

6.3 Cleaning

If cleaning after soldering is necessary, only specified solvents should be used. Unspecified chemicals may damage the LED's epoxy lens or package. The recommended method is to immerse the LED in ethyl alcohol or isopropyl alcohol at normal room temperature for less than one minute. Aggressive or ultrasonic cleaning is not advised.

7. Application Recommendations

7.1 Typical Application Scenarios

This high-brightness orange SMD LED is suitable for a wide range of applications requiring clear, visible indicator lights. Common uses include status indicators on consumer electronics (routers, printers, chargers), backlighting for small displays or icons, automotive interior lighting, signage, and general-purpose panel indicators. Its compatibility with automatic placement makes it ideal for cost-effective, high-volume production.

7.2 Drive Circuit Design

LEDs are current-operated devices. To ensure uniform brightness when driving multiple LEDs in parallel, it is strongly recommended to use a current-limiting resistor in series with each individual LED (Circuit Model A). Driving multiple LEDs in parallel directly from a single current source (Circuit Model B) is discouraged because small variations in the forward voltage (Vf) characteristic of each LED can cause significant differences in the current share and, consequently, the perceived brightness. The series resistor stabilizes the current through each LED.

7.3 Electrostatic Discharge (ESD) Protection

The LED is sensitive to electrostatic discharge. ESD damage can manifest as high reverse leakage current, low forward voltage, or failure to illuminate at low currents. Preventive measures must be implemented during handling and assembly: personnel should wear grounded wrist straps or anti-static gloves; all equipment, workbenches, and storage racks must be properly grounded; and an ionizer should be used to neutralize static charge that may accumulate on the plastic lens due to handling friction. Verifying \"light-up\" and Vf at low current can help identify ESD-damaged units.

8. Technical Comparison & Differentiation

The key differentiator of this LED is its use of an AlInGaP semiconductor material, which offers superior efficiency and color stability compared to older technologies like standard GaP for orange/red colors. The wide 130-degree viewing angle makes it suitable for applications requiring broad visibility, unlike narrow-beam LEDs. Its compliance with stringent reflow soldering profiles (both IR and vapor phase) indicates a robust package construction capable of withstanding standard SMT assembly thermal stress. The detailed binning system provides designers with precise control over brightness uniformity in their products.

9. Frequently Asked Questions (FAQs)

Q: What is the difference between peak wavelength and dominant wavelength?
A: Peak wavelength (\u03bbP) is the single wavelength at which the emitted optical power is maximum. Dominant wavelength (\u03bbd) is derived from the CIE chromaticity diagram and represents the single wavelength that best matches the perceived color of the light. For a monochromatic source like this LED, they are close, but \u03bbd is more relevant for color specification.

Q: Can I drive this LED at its maximum DC current of 30mA continuously?
A: While possible, it is not recommended for optimal lifetime and reliability. Operating at or near absolute maximum ratings increases junction temperature and accelerates degradation. Designers should use the typical operating condition of 20mA or lower for a better balance of brightness and longevity.

Q: Why is a baking process required before soldering if the parts have been stored for too long?
A> Plastic SMD packages can absorb moisture from the atmosphere. During the high-temperature reflow soldering process, this trapped moisture can vaporize rapidly, creating internal pressure that can crack the package or delaminate internal interfaces (\"popcorning\"). Baking drives out this absorbed moisture.

Q: How do I select the correct current-limiting resistor value?
A> Use Ohm's Law: R = (Vsupply - Vf_LED) / I_LED. For a 5V supply, a typical Vf of 2.4V, and a desired current of 20mA: R = (5 - 2.4) / 0.02 = 130 Ohms. Always use the maximum Vf from the datasheet (2.4V) for this calculation to ensure the current does not exceed the desired value under all conditions.

10. Design-in Case Study

Consider designing a status indicator panel for a network switch with ten identical orange LED indicators. To ensure uniform brightness, the designer specifies Bin Q (71-112 mcd) from the supplier. A drive circuit is designed using a 5V rail. Calculating the series resistor using the maximum Vf of 2.4V and a target current of 18mA (slightly below typical for margin) gives R = (5V - 2.4V) / 0.018A \u2248 144 Ohms. A standard 150 Ohm, 1% tolerance resistor is selected. Ten identical circuits are laid out on the PCB, each with its own resistor. The PCB footprint follows the recommended pad dimensions. The assembly house uses the provided lead-free reflow profile. Post-assembly, all ten LEDs exhibit consistent brightness within the expected Bin Q range, validating the design approach of using individual current-limiting resistors and careful bin selection.

11. Operating Principle

This LED operates on the principle of electroluminescence in a semiconductor p-n junction. The active region is composed of AlInGaP. When a forward voltage exceeding the diode's turn-on voltage (approximately 2.0V) is applied, electrons from the n-type region and holes from the p-type region are injected into the active region. When these charge carriers recombine, they release energy in the form of photons (light). The specific composition of the AlInGaP alloy determines the bandgap energy, which directly dictates the wavelength (color) of the emitted light\u2014in this case, orange at around 605-611 nm. The \"water clear\" lens allows the light to exit the package with minimal scattering, resulting in high axial intensity.

12. Technology Trends

The use of AlInGaP materials represents an established, high-efficiency technology for amber, orange, and red LEDs. Ongoing trends in the industry include the continued push for higher luminous efficacy (more light output per electrical watt), which improves energy efficiency. There is also a focus on enhancing color stability over temperature and operating life. Packaging trends aim for smaller form factors while maintaining or improving thermal performance to handle higher drive currents. Furthermore, integration with intelligent drivers and the development of LEDs compatible with even higher-temperature, lead-free soldering processes remain active areas of development to meet evolving environmental regulations and manufacturing demands.