SMD5050N Yellow LED Datasheet - 5.0x5.0x1.6mm - 2.2V - 0.234W - English Technical Document

1. Product Overview

The SMD5050N series is a high-brightness, surface-mount LED designed for applications requiring reliable yellow illumination. Characterized by its 5.0mm x 5.0mm footprint, this LED offers a wide 120-degree viewing angle and is suitable for a variety of lighting, signage, and indicator applications. Its primary advantage lies in its consistent performance and standardized binning system, ensuring color and luminous flux uniformity across production batches.

2. Technical Parameter Analysis

2.1 Absolute Maximum Ratings

The following parameters define the operational limits of the LED. Exceeding these values may cause permanent damage.

• Forward Current (IF): 90 mA (Continuous)
• Forward Pulse Current (IFP): 120 mA (Pulse width ≤10ms, Duty cycle ≤1/10)
• Power Dissipation (PD): 234 mW
• Operating Temperature (Topr): -40°C to +80°C
• Storage Temperature (Tstg): -40°C to +80°C
• Junction Temperature (Tj): 125°C
• Soldering Temperature (Tsld): Reflow soldering at 200°C or 230°C for 10 seconds maximum.

2.2 Typical Electrical & Optical Characteristics

Measured at a standard test condition of T_s=25°C and I_F=60mA.

• Forward Voltage (V_F): Typical 2.2V, Maximum 2.6V (±0.08V tolerance)
• Reverse Voltage (V_R): 5V
• Dominant Wavelength (λ_d): 590 nm (typical)
• Reverse Current (I_R): Maximum 10 µA
• Viewing Angle (2θ_1/2): 120 degrees

3. Binning System Explanation

To ensure consistency, LEDs are sorted (binned) based on key performance parameters.

3.1 Luminous Flux Binning

Binned at I_F=60mA. The luminous flux measurement has a tolerance of ±7%.

• Code A6: 2.5 lm (Min), 3 lm (Typ)
• Code A7: 3 lm (Min), 3.5 lm (Typ)
• Code A8: 3.5 lm (Min), 4 lm (Typ)
• Code A9: 4 lm (Min), 4.5 lm (Typ)
• Code B1: 4.5 lm (Min), 5 lm (Typ)

3.2 Dominant Wavelength Binning

Defines the specific shade of yellow light emitted.

• Code Y1: 585 nm to 588 nm
• Code Y2: 588 nm to 591 nm
• Code Y3: 591 nm to 594 nm

4. Performance Curve Analysis

Graphical data provides insight into the LED's behavior under varying conditions.

4.1 Forward Voltage vs. Forward Current (IV Curve)

This curve shows the relationship between the applied forward voltage and the resulting current. It is essential for designing appropriate current-limiting circuitry to prevent thermal runaway.

4.2 Forward Current vs. Relative Luminous Flux

This graph illustrates how light output scales with drive current. It typically shows a near-linear relationship within the recommended operating range, but efficiency may drop at very high currents due to increased heat.

4.3 Junction Temperature vs. Relative Spectral Power

This curve demonstrates the effect of junction temperature on the LED's spectral output. For yellow LEDs, increased temperature can cause a slight shift in dominant wavelength and a reduction in overall light output.

4.4 Spectral Power Distribution

This plot shows the intensity of light emitted across the visible spectrum, confirming the monochromatic nature of the yellow LED with a peak around 590nm.

5. Mechanical & Packaging Information

5.1 Physical Dimensions

The SMD5050N package measures 5.0mm in length, 5.0mm in width, and 1.6mm in height. Dimensional tolerances are specified as ±0.10mm for .X dimensions and ±0.05mm for .XX dimensions.

5.2 Recommended Pad & Stencil Design

For reliable soldering, a specific land pattern and stencil aperture design are recommended. The provided diagrams ensure proper solder joint formation, good thermal dissipation, and mechanical stability. The design typically features six pads (two for each internal LED chip in a common 3-chip configuration).

5.3 Polarity Identification

The LED package includes a polarity marking, usually a notch or a dot near the cathode pin. Correct orientation is crucial for circuit operation.

6. Soldering & Assembly Guidelines

6.1 Moisture Sensitivity & Baking

The SMD5050N LED is classified as moisture-sensitive (MSL). If the original sealed moisture barrier bag is opened and the components are exposed to ambient humidity beyond specified limits, they must be baked before reflow soldering to prevent \"popcorn\" damage.

• Storage Condition (Unopened): Temperature <30°C, Relative Humidity <85%.
• Storage Condition (Opened): Use within 12 hours or store in a dry cabinet (<20% RH or with nitrogen).
• Baking Requirement: Required if the humidity indicator card shows exposure or if exposed to air for >12 hours.
• Baking Method: 60°C for 24 hours on the original reel. Do not exceed 60°C. Use within 1 hour after baking or return to dry storage.

6.2 Reflow Soldering Profile

The LED can withstand a standard infrared or convection reflow process. The maximum peak temperature is 230°C or 200°C, with the time above liquidus not exceeding 10 seconds. Consult the specific profile for the solder paste used.

7. Electrostatic Discharge (ESD) Protection

LEDs are semiconductor devices susceptible to damage from electrostatic discharge.

7.1 ESD Damage Mechanisms

ESD can cause latent or catastrophic failure. Latent damage may increase leakage current and reduce lifespan, while catastrophic failure results in immediate non-operation (dead LED).

7.2 ESD Control Measures

• Use grounded anti-static workstations and floors.
• Personnel must wear grounded wrist straps, anti-static smocks, and gloves.
• Use ionizers to neutralize static charges in the work area.
• Ensure all tools (e.g., soldering irons) are properly grounded.
• Use conductive or dissipative materials for handling and packaging.

8. Application & Circuit Design Suggestions

8.1 Driving Methodology

For optimal performance and longevity, drive the LED with a constant current source. This ensures stable light output and protects the LED from current spikes and thermal variations. If using a constant voltage source, a series current-limiting resistor is mandatory for each LED string.

8.2 Recommended Circuit Configurations

Configuration A (With Individual Resistors): Each LED or parallel string has its own series resistor. This provides individual current regulation and is more tolerant of V_F variations between LEDs.
Configuration B (Series String with Single Resistor): Multiple LEDs are connected in series with one current-limiting resistor. This is more efficient but requires a higher voltage supply and all LEDs in the string must have closely matched V_F.

8.3 Assembly Precautions

• Always handle LEDs with ESD protection.
• Avoid touching the silicone lens with bare hands to prevent contamination from oils and salts, which can reduce light output.
• Use vacuum pick-up tools or soft-tipped tweezers to avoid mechanically damaging the soft silicone encapsulant or wire bonds.
• During system testing, connect the driver to the LED load before applying input power to avoid voltage transients.

9. Model Numbering Rule

The part number follows a structured format: T [Shape Code] [Chip Count] [Lens Code] - [Flux Code][Wavelength Code].
Example: T5A003YA decodes as:
- T: Manufacturer prefix.
- 5A: Shape code for 5050N package.
- 0: Internal code.
- 3: Three LED chips inside the package.
- YA: Yellow color, specific flux and wavelength bin (A for flux, Y for wavelength).
Other codes define lens type (00=none, 01=with lens) and various color options (R=Red, G=Green, B=Blue, etc.).

10. Typical Application Scenarios

The SMD5050N Yellow LED is well-suited for:
- Architectural & Decorative Lighting: Creating warm, accent lighting.
- Signage & Channel Letters: Providing uniform backlighting or illumination.
- Automotive Interior Lighting: Dashboard and courtesy lights.
- Consumer Electronics: Status indicators and backlighting for appliances.
- Full-Color RGB Modules: As the yellow component in tunable white or color-mixing systems (when used with appropriate phosphor-converted or other color LEDs).

11. Technical Comparison & Considerations

Compared to smaller packages like 3528, the 5050 offers higher total light output due to its larger size and ability to house multiple chips. Its 120-degree viewing angle is wider than some focused-lens LEDs, making it ideal for area illumination rather than spot lighting. Designers should consider thermal management, as the power dissipation (up to 234mW) requires adequate PCB copper area or heatsinking for maximum lifetime, especially when driven at high currents or in high ambient temperatures.

12. Frequently Asked Questions (FAQ)

Q: What is the difference between the luminous flux codes (A6, A7, etc.)?
A: These codes represent different brightness grades. A higher code (e.g., B1) indicates a higher minimum and typical luminous flux output. Select the bin based on the required brightness for your application.

Q: Is baking always necessary before soldering?
A: No. Baking is only required if the moisture-sensitive components have been exposed to humid environments beyond the limits specified on the bag's humidity indicator card or after prolonged storage outside a dry environment.

Q: Can I drive this LED at 90mA continuously?
A: While 90mA is the absolute maximum rating, continuous operation at this level will generate significant heat and likely reduce lifespan. For reliable long-term operation, it is advisable to drive the LED at or below the typical test current of 60mA, with proper thermal management.

Q: Why is a constant current driver recommended over a constant voltage source with a resistor?
A: A constant current driver compensates for the forward voltage (V_F) variation between LEDs and over temperature, ensuring consistent light output and preventing thermal runaway. It offers better stability and efficiency, especially for series strings.

13. Design-in Case Study

Scenario: Designing a backlight unit for an informational display panel.
1. Requirement: Uniform yellow illumination over a 200mm x 100mm area with a target illuminance of 150 lux.
2. LED Selection: SMD5050N (Code B1, 5 lm typical) is chosen for its brightness and wide viewing angle.
3. Optical Design: LEDs are arranged in a grid pattern with a diffuser sheet placed above to blend individual points into a uniform field. Spacing is calculated based on the LED's viewing angle and target uniformity.
4. Electrical Design: LEDs are grouped into parallel strings of 4 LEDs in series. A constant current driver is selected to provide 60mA per string. The driver output voltage must exceed the sum of the V_F of 4 LEDs (approx. 8.8V-10.4V) plus headroom.
5. Thermal Design: The PCB is designed with large copper pours connected to the LED thermal pads. Thermal vias transfer heat to a bottom-side copper layer. Calculations confirm the junction temperature remains below 80°C in a 40°C ambient environment.
6. Assembly: LEDs are placed using a pick-and-place machine. The assembled board is baked according to MSL guidelines before undergoing a controlled reflow soldering process. ESD precautions are maintained throughout.

14. Operational Principle

Light Emitting Diodes (LEDs) are semiconductor devices that emit light through electroluminescence. When a forward voltage is applied across the p-n junction, electrons from the n-type region recombine with holes from the p-type region in the active layer. This recombination process releases energy in the form of photons (light). The color of the light is determined by the energy bandgap of the semiconductor material used. For a monochromatic yellow LED like the SMD5050N, the semiconductor material (typically based on AlInGaP) is engineered to have a bandgap corresponding to a wavelength of approximately 590 nanometers.

15. Technology Trends

The LED industry continues to evolve towards higher efficiency (more lumens per watt), improved color rendering, and greater reliability. For monochromatic LEDs like yellow, trends include:
- Narrower Wavelength Binning: Tighter control over dominant wavelength for more precise color applications.
- Higher Temperature Operation: Development of materials and packaging that maintain performance at higher junction temperatures.
- Miniaturization with High Output: Smaller package sizes delivering light output comparable to larger legacy packages.
- Integrated Solutions: LEDs with built-in current regulation, protection circuits (ESD, over-temperature), or even microcontrollers for smart lighting applications.
- Advanced Phosphors: For white and broad-spectrum LEDs, but also affecting the stability and quality of certain colored LEDs.