LTL17KYV3JS LED Lamp Datasheet - T-1 3mm Round - Yellow 596nm - 2.4V Max - 120mW - English Technical Document

1. Product Overview

The LTL17KYV3JS is a high-performance, through-hole LED lamp designed for demanding visual applications. It features a popular T-1 (3mm) round package with a white diffused lens, providing a smooth and uniform viewing angle radiation pattern. The device utilizes AlInGaP technology to produce a vibrant yellow light with a peak emission wavelength of 596nm.

1.1 Core Advantages and Target Market

This LED is engineered for applications requiring high visibility and reliability. Its key advantages include a high luminous intensity output, which translates to excellent brightness and power efficiency. The package incorporates advanced epoxy technology with UV inhibitors, offering superior moisture resistance and protection against long-term outdoor environmental exposure. The primary target markets are full-color signage, including RGB full-color signs, billboard signs, message signs, and bus signs, where consistent color and brightness are critical.

2. Technical Parameter Deep-Dive

This section provides an objective analysis of the LED's key electrical, optical, and thermal characteristics as defined in the datasheet.

2.1 Absolute Maximum Ratings

The device is rated for a maximum power dissipation of 120mW at an ambient temperature (TA) of 25°C. The absolute maximum DC forward current is 50mA. For pulsed operation with a duty cycle ≤ 1/10 and pulse width ≤ 10ms, the peak forward current can reach 120mA. The operating temperature range is specified from -40°C to +85°C, with storage up to +100°C. The derating factor for forward current is 0.67 mA/°C linearly from 30°C upwards, meaning the permissible continuous current decreases as temperature increases to stay within the power dissipation limit.

2.2 Electrical & Optical Characteristics

Under standard test conditions (TA=25°C, IF=20mA), the typical luminous intensity (Iv) is 5500 millicandelas (mcd). The viewing angle (2θ1/2), defined as the off-axis angle where intensity drops to half its axial value, is 30 degrees. The forward voltage (Vf) typically ranges from 1.8V to 2.4V at 20mA. The reverse current (IR) is a maximum of 100µA at a reverse voltage (VR) of 5V, but the device is not designed for reverse-bias operation. The spectral characteristics include a peak wavelength (λP) of 596nm and a typical spectral half-width (Δλ) of 15nm.

3. Binning System Specification

To ensure consistency in production batches, the LEDs are sorted into bins based on key parameters. This allows designers to select parts that meet specific application requirements for brightness, voltage, and color.

3.1 Luminous Intensity Binning

Luminous intensity is classified into codes U, V, W, and X, with minimum and maximum ranges (e.g., V: 4200-5500 mcd, W: 5500-7200 mcd). A tolerance of ±15% is applied to each bin limit during testing.

3.2 Forward Voltage Binning

Forward voltage is binned into codes 1A, 2A, and 3A, corresponding to Vf ranges of 1.8-2.0V, 2.0-2.2V, and 2.2-2.4V respectively, with a ±0.1V tolerance per bin.

3.3 Dominant Wavelength Binning

Dominant wavelength, which defines the perceived color, is binned into four codes (1-4) covering the range from 584.5nm to 594.5nm in approximately 2.5nm steps, with a ±1nm tolerance.

4. Performance Curve Analysis

While specific graphs are referenced in the datasheet (Fig.1, Fig.6), typical curves for such a device would illustrate the relationship between forward current and luminous intensity (showing a near-linear increase within limits), the forward voltage vs. current (exponential turn-on characteristic), and the relative intensity vs. temperature (showing a decrease in output as junction temperature rises). The 30-degree viewing angle pattern indicates a relatively focused beam compared to wide-angle LEDs.

5. Mechanical & Package Information

The LED conforms to the standard T-1 (3mm) round through-hole package dimensions. Key mechanical notes include: a lead spacing measured where leads emerge from the package, a tolerance of ±0.25mm unless specified, and a maximum resin protrusion under the flange of 1.0mm. The white diffused epoxy lens provides a uniform light appearance and helps in color mixing for RGB applications.

6. Soldering & Assembly Guidelines

Proper handling is crucial for reliability. Leads must be formed at a point at least 3mm from the lens base before soldering, without using the lead frame as a fulcrum. During PCB assembly, minimal clinch force should be used.

6.1 Soldering Parameters

For hand soldering, the iron tip temperature should not exceed 350°C, with a maximum soldering time of 3 seconds per lead, and the solder point must be at least 3mm from the lens base. For wave soldering, pre-heat should be below 100°C for up to 60 seconds, with a solder wave at 260°C max for 5 seconds, ensuring the lens is not dipped. IR reflow is explicitly stated as unsuitable for this through-hole product.

6.2 Storage & Cleaning

LEDs should be stored below 30°C and 70% relative humidity. Out-of-packaging, they should be used within three months or stored in a sealed, dry environment. Isopropyl alcohol is recommended for cleaning if necessary.

7. Packaging & Ordering Information

The standard packaging is 1000, 500, or 250 pieces per anti-static bag. Eight bags are packed into an inner carton (8000 pcs total). Eight inner cartons constitute an outer shipping carton (64,000 pcs total). Partial packs may occur in the final pack of a shipping lot. The part number LTL17KYV3JS uniquely identifies this specific yellow LED variant.

8. Application Recommendations

8.1 Typical Application Scenarios

This LED is optimized for indoor and outdoor full-color dynamic signage. Its high intensity and specific yellow wavelength make it ideal for blending with red and green LEDs to create a wide color gamut in billboards, bus destination signs, and informational message displays.

8.2 Circuit Design Considerations

LEDs are current-driven devices. To ensure uniform brightness when using multiple LEDs in parallel, it is strongly recommended to use a individual current-limiting resistor in series with each LED (Circuit A in the datasheet). Driving multiple LEDs in parallel directly from a voltage source (Circuit B) is discouraged due to variations in forward voltage (Vf) between individual LEDs, which can cause significant differences in current and, consequently, brightness.

8.3 ESD (Electrostatic Discharge) Protection

The LED is sensitive to electrostatic discharge. Preventive measures include using grounded wrist straps and workstations, employing ionizers to neutralize static on the lens, and ensuring all handling equipment is properly grounded.

9. Technical Comparison & Differentiation

Compared to standard indicator LEDs, the LTL17KYV3JS offers significantly higher luminous intensity (5500+mcd typical), making it suitable for daylight-visible signage rather than just panel indication. The use of AlInGaP material provides higher efficiency and better temperature stability for the yellow spectrum compared to older technologies. The inclusion of a detailed binning system for intensity, voltage, and wavelength allows for tighter color and brightness matching in large-scale display assemblies, a critical factor for professional signage.

10. Frequently Asked Questions (Based on Technical Parameters)

Q: What is the difference between peak wavelength (596nm) and dominant wavelength (584.5-594.5nm)?
A: Peak wavelength is the point of maximum power in the spectral output. Dominant wavelength is derived from the color coordinates and represents the single wavelength of the pure spectral color that matches the LED's perceived hue. They are related but not identical metrics for color.

Q: Can I drive this LED at 50mA continuously?
A: While the absolute maximum rating is 50mA DC, continuous operation at this current will generate significant heat. The actual safe operating current depends on the ambient temperature and thermal management, as dictated by the power dissipation rating (120mW max) and derating curve. At 25°C, 50mA with a typical Vf of 2.2V results in 110mW, which is within limits but leaves little margin. For reliability, operating at or below the test condition of 20mA is common.

Q: Why is a series resistor necessary for each LED in parallel?
A> The forward voltage (Vf) has a tolerance and binning range (1.8V-2.4V). A small difference in Vf between two LEDs connected in parallel to a voltage source will cause a large disparity in the current each draws due to the diode's exponential I-V curve. A series resistor for each LED makes the current much less sensitive to Vf variations, ensuring uniform brightness.

11. Practical Design Case Study

Consider designing a cluster for a full-color pixel in an outdoor sign. A pixel might use one red, one green, and one LTL17KYV3JS (yellow) LED. To achieve white balance and target brightness, the drive currents for each color may be different and controlled via PWM (Pulse Width Modulation). The designer would select LEDs from appropriate intensity bins (e.g., V or W bin) to ensure the yellow channel's output matches the red and green. Separate current-limiting resistors would be used for each LED, calculated based on the supply voltage and the LED's typical Vf from its bin code (e.g., 2A bin: ~2.1V). The PCB layout would maintain the minimum 3mm clearance from the lens for soldering and provide adequate spacing for heat dissipation.

12. Operating Principle Introduction

The LTL17KYV3JS is based on Aluminum Indium Gallium Phosphide (AlInGaP) semiconductor material. When a forward voltage is applied across the P-N junction, electrons and holes recombine in the active region, releasing energy in the form of photons. The specific composition of the AlInGaP layers determines the bandgap energy, which directly corresponds to the wavelength of light emitted—in this case, yellow (~596nm). The epoxy lens serves to protect the semiconductor die, shape the radiation pattern to a 30-degree viewing angle, and diffuse the light for a uniform appearance.

13. Technology Trends

In the signage LED market, trends include continued increases in luminous efficacy (lumens per watt), allowing for brighter displays or lower power consumption. There is also a move towards tighter binning tolerances for both color and intensity to enable seamless large-area displays without visible color or brightness variations. While surface-mount device (SMD) LEDs dominate new designs for compactness, through-hole LEDs like the T-1 package remain relevant for applications requiring robust mechanical mounting, easier manual assembly, or specific optical characteristics from the traditional dome lens shape.