LTST-C19HRGYW Full Color SMD LED Datasheet - Package Dimensions - Red/Green/Yellow - 30mA - English Technical Document

1. Product Overview

The LTST-C19HRGYW is a full-color, surface-mount LED designed for modern electronic applications requiring compact size and automated assembly. This device integrates three distinct LED chips within a single, extra-thin package, enabling versatile color indication and backlighting solutions.

1.1 Core Advantages

This LED offers several key advantages for design engineers. Its primary benefit is the integration of three light sources (Red, Green, Yellow) into one miniature footprint, saving valuable PCB space. The package is exceptionally thin, measuring only 0.35mm in height, making it suitable for ultra-slim devices. It is fully compliant with RoHS directives and is designed for compatibility with standard infrared reflow soldering processes, facilitating high-volume, automated manufacturing.

1.2 Target Market and Applications

The device is targeted at a broad range of consumer and industrial electronics. Its primary applications include status indicators and backlighting for keypads or keyboards in telecommunications equipment such as cordless and cellular phones. It is also well-suited for use in office automation products like notebook computers, network systems, various home appliances, and indoor signage or symbol luminaires. The combination of colors allows for multi-status indication in a single component.

2. In-Depth Technical Parameter Analysis

The following sections provide a detailed breakdown of the device's operational limits and performance characteristics under standard conditions.

2.1 Absolute Maximum Ratings

These ratings define the stress limits beyond which permanent damage to the device may occur. The absolute maximum ratings are specified at an ambient temperature (Ta) of 25°C. The power dissipation is 75mW for the Red and Yellow chips, and 80mW for the Green chip. The maximum continuous DC forward current is 30mA for Red and Yellow, and 20mA for Green. A higher peak forward current of 80mA (Red/Yellow) and 100mA (Green) is allowed under pulsed conditions (1/10 duty cycle, 0.1ms pulse width). The device can operate within a temperature range of -20°C to +80°C and be stored from -30°C to +85°C. It can withstand infrared reflow soldering at 260°C for a maximum of 10 seconds.

2.2 Electrical and Optical Characteristics

These parameters define the typical performance when operated within the recommended conditions at Ta=25°C. Luminous intensity (Iv) is measured at a forward current (If) of 20mA. For the Red chip, Iv ranges from a minimum of 45.0 mcd to a maximum of 180.0 mcd. The Green chip offers a higher output, ranging from 71.0 mcd to 450.0 mcd. The Yellow chip ranges from 71.0 mcd to 280.0 mcd. The device features a very wide viewing angle (2θ1/2) of 130 degrees, providing broad, diffuse illumination. The peak emission wavelengths (λP) are 632.0 nm (Red), 520.0 nm (Green), and 595.0 nm (Yellow). The corresponding dominant wavelength (λd) ranges are 617-631 nm (Red), 520-530 nm (Green), and 587-602 nm (Yellow). Forward voltage (Vf) at 20mA ranges from 1.8V to 2.4V for Red and Yellow, and from 2.9V to 3.5V for Green. The maximum reverse current (Ir) is 10 μA at a reverse voltage (Vr) of 5V for all colors.

3. Binning System Explanation

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

3.1 Luminous Intensity Binning

The binning system categorizes LEDs by their measured light output at 20mA. Each bin has a defined minimum and maximum value, with a tolerance of +/-15% within each bin. For the Red chip, bins are labeled P (45.0-71.0 mcd), Q (71.0-112.0 mcd), and R (112.0-180.0 mcd). The Green chip uses bins Q (71.0-112.0 mcd), R (112.0-180.0 mcd), S (180.0-280.0 mcd), and T (280.0-450.0 mcd). The Yellow chip is binned as Q (71.0-112.0 mcd), R (112.0-180.0 mcd), and S (180.0-280.0 mcd). This system allows designers to select components that meet specific brightness requirements for their application.

4. Performance Curve Analysis

While specific graphical data is referenced in the datasheet, typical curves for this type of device would illustrate key relationships. The forward current vs. forward voltage (I-V) curve shows the exponential relationship, critical for designing current-limiting circuitry. The relative luminous intensity vs. forward current curve demonstrates how light output increases with current, up to the maximum rating. The spectral distribution curve would show the narrow emission bands characteristic of AlInGaP (Red/Yellow) and InGaN (Green) semiconductor materials, defining the pure color output. Understanding these curves is essential for optimizing drive conditions and predicting performance under different operating scenarios.

5. Mechanical and Package Information

5.1 Package Dimensions and Pin Assignment

The LTST-C19HRGYW conforms to a standard EIA package outline. The lens color is white diffused. The internal source colors and their corresponding pin assignments are: Pin 1 for the AlInGaP Red chip, Pin 2 for the InGaN Green chip, and Pin 3 for the AlInGaP Yellow chip. All dimensional tolerances are ±0.1 mm unless otherwise specified. The exact mechanical drawing should be consulted for critical placement and clearance calculations.

5.2 Recommended PCB Attachment Pad

A recommended land pattern (footprint) is provided to ensure reliable soldering and proper mechanical alignment during the reflow process. Adhering to this pattern helps prevent tombstoning (component standing on end) and ensures good solder fillet formation, which is crucial for both electrical connection and mechanical strength.

6. Soldering and Assembly Guidelines

6.1 IR Reflow Soldering Parameters

For lead-free (Pb-free) soldering processes, a specific temperature profile is recommended. The peak body temperature should not exceed 260°C, and the time above 260°C should be limited to a maximum of 10 seconds. A pre-heat stage is also defined. It is critical to follow these guidelines to prevent thermal damage to the LED package, such as delamination or cracking, which can degrade performance or cause failure.

6.2 Storage and Handling Conditions

Proper handling is essential for reliability. The device is sensitive to electrostatic discharge (ESD); therefore, anti-static precautions like wrist straps and grounded equipment are mandatory during handling. For storage, unopened moisture-proof bags (with desiccant) should be kept at ≤30°C and ≤90% RH, with a shelf life of one year. Once opened, components should be stored at ≤30°C and ≤60% RH and should undergo IR reflow within one week (Moisture Sensitivity Level 3, MSL 3). If stored longer out of the original bag, a bake-out at 60°C for at least 20 hours is required 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. Immersing the LED in ethyl alcohol or isopropyl alcohol at normal temperature for less than one minute is acceptable. Unspecified chemical cleaners may damage the plastic package or lens.

7. Packaging and Ordering Information

The LEDs are supplied in a tape-and-reel format compatible with automated pick-and-place machines. The tape width is 8mm, wound onto 7-inch diameter reels. Each reel contains 4000 pieces. For quantities less than a full reel, a minimum packing quantity of 500 pieces is available. The packaging conforms to ANSI/EIA 481 specifications. The tape is sealed with a cover tape to protect components, and the maximum allowable number of consecutive missing components in the tape is two.

8. Application Suggestions and Design Considerations

8.1 Typical Application Circuits

Each color chip within the package must be driven independently. A typical drive circuit involves a current-limiting resistor in series with each anode (pin). The resistor value is calculated using Ohm's Law: R = (Vcc - Vf) / If, where Vcc is the supply voltage, Vf is the forward voltage of the specific LED chip (use max value from datasheet for reliability), and If is the desired forward current (not to exceed the DC rating). For multiplexing or advanced control, constant current drivers or PWM (Pulse Width Modulation) can be used to adjust brightness and create color mixing effects between the three channels.

8.2 Design Considerations and Cautions

This LED is intended for general-purpose electronic equipment. For applications requiring exceptional reliability where failure could jeopardize safety (e.g., aviation, medical devices), consultation with the component supplier is necessary prior to design. The device is not designed for reverse voltage operation; applying reverse bias beyond the test condition (5V) may cause damage. Thermal management should be considered if operating near maximum current ratings or in high ambient temperatures, as excessive heat can reduce luminous output and lifespan. The wide viewing angle makes it excellent for area illumination but may require light guides or diffusers for specific beam shaping.

9. Technical Comparison and Differentiation

The key differentiator of the LTST-C19HRGYW is its multi-chip, full-color capability in an extra-thin SMD package. Compared to using three discrete single-color LEDs, it offers significant space savings on the PCB and simplifies the assembly process. The use of AlInGaP technology for Red and Yellow provides high efficiency and good color purity, while InGaN technology is used for the Green chip. The 130-degree viewing angle is notably wide, offering more uniform illumination compared to narrower-angle devices. Its compatibility with standard IR reflow processes aligns it with mainstream SMT assembly lines.

10. Frequently Asked Questions (Based on Technical Parameters)

Q: Can I drive all three colors simultaneously at their maximum DC current?
A: No. The power dissipation and thermal limits of the shared package must be considered. Driving all three chips at their individual max DC current (30mA+20mA+30mA=80mA total) would likely exceed the package's thermal capacity unless excellent heat sinking is provided. It is advisable to consult derating curves or operate at lower currents for simultaneous full-power operation.

Q: What is the difference between peak wavelength and dominant wavelength?
A: Peak wavelength (λP) is the wavelength at which the emission spectrum has its maximum intensity. Dominant wavelength (λd) is derived from the CIE chromaticity diagram and represents the single wavelength of the pure spectral color that matches the perceived color of the LED. λd is more closely related to human color perception.

Q: How do I interpret the bin code when ordering?
A: The bin code (e.g., R for Red) specifies the guaranteed range of luminous intensity for that particular LED. You must specify the desired bin code(s) for each color when ordering to ensure your design receives LEDs with the brightness characteristics required for consistent product appearance and performance.

11. Practical Application Example

Scenario: Status Indicator for a Network Router
A designer needs a single indicator to show multiple system states: Off (no light), Booting (Yellow blinking), Normal Operation (Green solid), Network Error (Red solid), and Data Activity (Green blinking). The LTST-C19HRGYW is an ideal choice. A microcontroller GPIO pin can be connected to each cathode (with appropriate current-limiting resistors on the common anode side). Software can then control each color independently: turning on Yellow for boot, Green for normal, Red for error, and toggling Green for data activity. This replaces three separate LEDs, saving board space and component count while providing a clean, multi-state indication from a single point.

12. Operating Principle Introduction

Light Emitting Diodes (LEDs) are semiconductor devices that emit light when an electric current passes through them. This phenomenon is called electroluminescence. In the LTST-C19HRGYW, two different semiconductor material systems are used. The Red and Yellow chips are made from Aluminium Indium Gallium Phosphide (AlInGaP), which is efficient for producing light in the red to yellow-orange spectrum. The Green chip is made from Indium Gallium Nitride (InGaN), which is the standard material for producing blue and green light. When forward-biased, electrons and holes recombine in the semiconductor's active region, releasing energy in the form of photons (light). The specific color of the light is determined by the bandgap energy of the semiconductor material.

13. Technology Trends

The development of SMD LEDs like the LTST-C19HRGYW follows several key industry trends. There is a continuous drive towards miniaturization, allowing for more components and features in smaller devices. Higher efficiency is another major trend, leading to greater luminous output per unit of electrical power (higher efficacy), which is crucial for battery-powered applications. Improved color rendering and tighter binning tolerances are also areas of focus, enabling more consistent and accurate color production in displays and lighting. Furthermore, enhanced reliability and robustness for harsh environments, along with compatibility with higher-temperature soldering processes, are ongoing developments to meet the demands of advanced automotive and industrial applications.