LED Lamp 1254-10SYGD/S530-E2 Datasheet - 5.0mm Round - 2.0V - 20mA - Brilliant Yellow Green - English Technical Document

3. Performance Curve Analysis

The datasheet provides several characteristic curves that are crucial for understanding device behavior under non-standard conditions.

3.1 Relative Intensity vs. Wavelength

This curve shows the spectral distribution of the emitted light, centered around 575nm with a typical spectral bandwidth (Δλ) of 20nm. It confirms the monochromatic nature of the AlGaInP chip.

3.2 Directivity Pattern

The polar plot illustrates the spatial distribution of light, correlating with the 40° viewing angle. It shows a typical Lambertian or near-Lambertian emission pattern common for diffused lens LEDs.

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

This exponential curve is fundamental for driver design. It shows the relationship between applied voltage and resulting current. The "knee" voltage is around 1.8V-2.0V, after which current increases rapidly with small voltage increments, highlighting the need for current control, not voltage control.

3.4 Relative Intensity vs. Forward Current

This curve demonstrates the super-linear relationship between drive current and light output. While increasing current boosts brightness, it also increases junction temperature and can accelerate lumen depreciation if maximum ratings are exceeded.

3.5 Temperature Dependence Curves

Relative Intensity vs. Ambient Temperature: Shows the light output decreasing as ambient temperature (T_a) rises. This thermal derating is critical for applications in high-temperature environments.
Forward Current vs. Ambient Temperature: Under constant voltage bias, the forward current would typically increase with temperature for a diode. This curve likely shows the necessary current adjustment to maintain a parameter, emphasizing the importance of thermal management.

4. Mechanical & Package Information

4.1 Package Dimensions

The LED features a standard 5mm round radial leaded package. Key dimensions include:

• Overall diameter: 5.0mm (nominal).
• Lead spacing: 2.54mm (standard 0.1-inch pitch).
• Total height is constrained, with the flange height specified to be less than 1.5mm.
• Standard tolerance for dimensions is ±0.25mm unless otherwise specified.

The mechanical drawing is essential for PCB footprint design, ensuring proper fit and alignment.

4.2 Polarity Identification

The cathode is typically identified by a flat spot on the lens rim or a shorter lead. The datasheet drawing should be consulted for the specific marker used on this model to ensure correct orientation during assembly.

5. Soldering & Assembly Guidelines

Proper handling is vital for reliability. The datasheet provides detailed instructions.

5.1 Lead Forming

• Bending must occur at least 3mm from the epoxy bulb base to avoid stress on the seal.
• Forming must be done before soldering, at room temperature.
• PCB hole alignment must be precise to avoid mounting stress.

5.2 Soldering Process

Hand Soldering: Iron tip temperature ≤300°C (30W max), time ≤3 seconds per lead. Maintain ≥3mm distance from solder joint to epoxy bulb.
Wave/DIP Soldering: Preheat ≤100°C (≤60 sec). Solder bath at ≤260°C for ≤5 seconds. Maintain ≥3mm distance from solder joint to epoxy bulb.
General Rules: Avoid stress on leads at high temperature. Do not solder more than once. Allow to cool to room temperature gradually, protected from shock/vibration. Use the lowest effective temperature.

5.3 Recommended Soldering Profile

A graphical profile is provided, typically showing a gradual preheat, a defined time above liquidus (e.g., 260°C), and a controlled cooling rate. Adherence to this profile prevents thermal shock.

5.4 Cleaning

If necessary, clean only with isopropyl alcohol at room temperature for ≤1 minute. Do not use ultrasonic cleaning unless pre-qualified, as it can damage the internal structure.

5.5 Storage Conditions

Store at ≤30°C and ≤70% Relative Humidity. Shelf life after shipping is 3 months. For longer storage (up to 1 year), use a sealed container with nitrogen atmosphere and desiccant. Avoid rapid temperature changes in humid environments to prevent condensation.

6. Thermal & Electrical Management

6.1 Heat Management

LED performance and lifetime are strongly temperature-dependent. Design must consider:

• Current Derating: The operating current should be reduced appropriately at higher ambient temperatures, as indicated by derating curves (implied in the datasheet notes).
• Ambient Control: The temperature around the LED in the final application must be managed, often through PCB layout, heatsinking, or airflow.

6.2 ESD (Electrostatic Discharge) Sensitivity

The LED chip is sensitive to electrostatic discharge and surge voltage. Standard ESD precautions should be observed during handling and assembly, such as using grounded workstations and wrist straps.

7. Packaging & Ordering Information

7.1 Packing Specification

The LEDs are packed to ensure moisture resistance and protection from electrostatic and electromagnetic fields.

• Primary Packing: Anti-electrostatic bag.
• Secondary Packing: Inner carton containing 4 bags.
• Tertiary Packing: Outside carton containing 10 inner cartons.
• Packing Quantity: Minimum 200 to 1000 pieces per bag. Standard outside carton contains 40 bags (from 8,000 to 40,000 pieces depending on bag count).

7.2 Label Explanation

The packing label includes several codes for traceability and binning:

• CPN: Customer's Production Number.
• P/N: Manufacturer's Production Number (1254-10SYGD/S530-E2).
• QTY: Quantity in the package.
• CAT: Ranks of Luminous Intensity (Brightness bin).
• HUE: Ranks of Dominant Wavelength (Color bin).
• REF: Ranks of Forward Voltage (Voltage bin).
• LOT No: Manufacturing lot number for traceability.

8. Application Design Considerations

8.1 Circuit Design

Always use a series current-limiting resistor. Calculate the resistor value (R) using: R = (V_supply - V_F) / I_F. Use the maximum V_F from the datasheet (2.4V) to ensure current does not exceed limits under worst-case conditions. For a 5V supply and 20mA target: R = (5V - 2.4V) / 0.02A = 130Ω. Use the next standard value (e.g., 150Ω) for a margin of safety.

8.2 PCB Layout

Ensure hole spacing matches the 2.54mm lead spacing. Provide adequate copper area or thermal relief around the leads if high currents or continuous operation is expected, to help dissipate heat.

8.3 Optical Integration

The 40° viewing angle and diffused lens provide a wide, soft light pattern suitable for panel indicators. For focused illumination, external optics may be required. The green diffused resin helps in achieving uniform color appearance.

9. Technical Comparison & Differentiation

While specific competitor data isn't provided, key differentiators of this part based on its datasheet include:

• Material Technology: Use of AlGaInP semiconductor material, which is highly efficient for producing yellow, orange, red, and green wavelengths, often offering higher brightness and efficiency than older technologies for these colors.
• Compliance: Comprehensive compliance with modern environmental regulations (RoHS, REACH, Halogen-Free) is a significant advantage for products targeting global markets, especially Europe.
• Robust Specifications: Clear absolute maximum ratings and detailed handling/soldering guidelines contribute to higher assembly yield and field reliability compared to parts with less thorough documentation.

10. Frequently Asked Questions (FAQ)

Q1: Can I drive this LED at 25mA continuously?
A1: The Absolute Maximum Rating for continuous forward current is 25mA. For reliable long-term operation, it is standard practice to derate this value. Operating at the typical 20mA condition is recommended for optimal lifetime and stability.

Q2: The luminous intensity is 40-63 mcd. Why the range?
A2: This range represents the manufacturing variation. LEDs are typically sorted into brightness bins (the "CAT" on the label). For consistent brightness in an application, specify or select LEDs from the same bin.

Q3: Is a heatsink required?
A3: For operation at 20mA in moderate ambient temperatures, a dedicated heatsink is usually not required for a single LED. However, thermal management at the PCB level (copper pads) is good practice. For arrays, higher currents, or high ambient temperatures, thermal analysis is necessary.

Q4: Can I use this for outdoor applications?
A4: The operating temperature range extends to -40°C, which suits many outdoor environments. However, the package is not specifically rated for waterproofing or UV resistance. For direct outdoor exposure, additional environmental protection (conformal coating, enclosures) would be required.

11. Design-in Case Study Example

Scenario: Designing a status indicator panel for a network router.
Requirement: Multiple yellow-green LEDs to show link activity and power status.
Design Steps:
1. Current Setting: Choose 15mA drive current per LED to ensure good visibility while providing margin below the 25mA maximum, enhancing longevity.
2. Circuit Calculation: With a 3.3V system rail and using max V_F=2.4V: R = (3.3V - 2.4V) / 0.015A = 60Ω. Use 62Ω 5% resistor.
3. PCB Design: Place LEDs on 2.54mm grid. Use small thermal relief pads for the leads. Group LEDs to simplify routing.
4. Assembly: Follow the specified wave soldering profile (260°C, 5s max). Ensure no solder wicking within 3mm of the epoxy bulb.
5. Result: A reliable, consistently bright indicator panel with uniform color, suitable for high-volume manufacturing.

12. Technology Principle Introduction

This LED is based on an AlGaInP (Aluminum Gallium Indium Phosphide) semiconductor chip. When forward voltage is applied, electrons and holes recombine in the active region of the PN junction, releasing energy in the form of photons (light). The specific color (brilliant yellow-green, 573nm) is determined by the bandgap energy of the AlGaInP alloy composition. The green diffused epoxy resin package serves multiple purposes: it acts as a lens to shape the light output, provides mechanical protection, and incorporates phosphors or dyes to modify the appearance and diffusion of the light emitted from the chip.

13. Industry Trends & Context

While surface-mount device (SMD) LEDs dominate new designs for miniaturization, through-hole LEDs like the 5mm round package remain relevant for several reasons: they are ideal for prototyping, breadboarding, and applications requiring high single-point brightness or where through-hole mounting is preferred for mechanical strength. The trend for such components is towards higher efficiency (more lumens per watt), tighter color and brightness binning for consistency, and guaranteed compliance with evolving environmental and safety standards. The detailed soldering and handling guidelines reflect the industry's focus on improving manufacturing yield and long-term reliability in automated production environments.