SMD LED 1206 Red 639nm Datasheet - Package 3.2x1.6x1.1mm - Forward Voltage 1.6-2.4V - Luminous Intensity 18-180mcd - English Technical Document

1. Product Overview

This document details the specifications for a high-performance, surface-mount AlInGaP (Aluminum Indium Gallium Phosphide) LED emitting red light. The device is designed for applications requiring high brightness and reliability in a compact, industry-standard 1206 package footprint. Its primary advantages include compatibility with automated pick-and-place equipment and infrared (IR) reflow soldering processes, making it suitable for high-volume manufacturing.

The LED utilizes an AlInGaP semiconductor chip, which is known for its high efficiency and stability in producing red, orange, and yellow wavelengths. The "Water Clear" lens material provides a wide viewing angle and helps achieve the specified luminous intensity. The product is compliant with RoHS (Restriction of Hazardous Substances) directives.

2. Technical Parameter Deep-Dive

2.1 Absolute Maximum Ratings

These ratings define the limits beyond which permanent damage to the device may occur. Operation under these conditions is not guaranteed.

• Power Dissipation (Pd): 62.5 mW. This is the maximum amount of power the LED package can dissipate as heat without exceeding its thermal limits.
• Peak Forward Current (I_F(peak)): 60 mA. This is the maximum allowable instantaneous forward current, typically specified under pulsed conditions (1/10 duty cycle, 0.1ms pulse width) to prevent overheating.
• DC Forward Current (I_F): 25 mA. This is the maximum continuous forward current recommended for reliable long-term operation.
• Reverse Voltage (V_R): 5 V. Exceeding this voltage in reverse bias can cause junction breakdown.
• Operating Temperature Range (T_opr): -30°C to +85°C. The ambient temperature range within which the LED will function according to its specifications.
• Storage Temperature Range (T_stg): -40°C to +85°C.
• Infrared Soldering Condition: 260°C for 10 seconds. The maximum thermal profile the package can withstand during reflow soldering.

2.2 Electro-Optical Characteristics

These parameters are measured at a standard test condition of Ta=25°C and I_F=20mA, unless otherwise noted.

• Luminous Intensity (I_V): 18.0 - 180.0 mcd (millicandela). The amount of visible light emitted, measured on-axis. The wide range indicates a binning system is used (see Section 3).
• Viewing Angle (2θ_1/2): 130 degrees. This is the full angle at which the luminous intensity drops to half of its peak (on-axis) value. A wide 130° angle indicates a diffuse, non-focused emission pattern suitable for area illumination.
• Peak Emission Wavelength (λ_P): 639 nm (typical). The wavelength at which the spectral power output is maximum.
• Dominant Wavelength (λ_d): 631 nm (typical at I_F=20mA). This is the single wavelength perceived by the human eye that best represents the color of the LED, derived from the CIE chromaticity diagram.
• Spectral Line Half-Width (Δλ): 20 nm (typical). The bandwidth of the emitted spectrum measured at half the peak intensity. A value of 20nm is characteristic of AlInGaP red LEDs.
• Forward Voltage (V_F): 1.60 - 2.40 V at I_F=20mA. The voltage drop across the LED when operating. Variation is due to semiconductor process tolerances.
• Reverse Current (I_R): 10 μA (max) at V_R=5V. The small leakage current when the LED is reverse-biased.

3. Binning System Explanation

To ensure consistency in applications, LEDs are sorted (binned) based on key parameters. This device is binned primarily for Luminous Intensity.

3.1 Luminous Intensity Binning

The luminous intensity is categorized into several bins, each with a minimum and maximum value. The tolerance on each bin is +/-15%.

• Bin M: 18.0 - 28.0 mcd
• Bin N: 28.0 - 45.0 mcd
• Bin P: 45.0 - 71.0 mcd
• Bin Q: 71.0 - 112.0 mcd
• Bin R: 112.0 - 180.0 mcd

Designers must select the appropriate bin based on their brightness requirements. Using a current-limiting resistor in series with each LED (as shown in the drive method section) is critical when using multiple LEDs in parallel to ensure uniform brightness, as V_F variations can cause current imbalance.

4. Performance Curve Analysis

While specific graphs are referenced in the datasheet (e.g., Fig.1, Fig.5), the typical behavior can be described based on the technology.

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

The AlInGaP LED exhibits a typical diode I-V characteristic. The forward voltage (V_F) has a negative temperature coefficient, meaning it decreases slightly as the junction temperature increases. The specified V_F range of 1.6V to 2.4V at 20mA must be considered for power supply design.

4.2 Luminous Intensity vs. Forward Current

Luminous intensity is approximately proportional to the forward current in the normal operating range (up to the DC forward current rating of 25mA). Operating above this current leads to increased heat generation, efficiency droop, and accelerated lumen depreciation.

4.3 Temperature Dependence

The luminous output of AlInGaP LEDs decreases as the junction temperature rises. This characteristic is crucial for designs where the LED may operate in elevated ambient temperatures or where thermal management is challenging. The operating temperature range of -30°C to +85°C defines the limits for maintaining specified performance.

4.4 Spectral Distribution

The emission spectrum is centered around a peak wavelength of 639nm (typical) with a half-width of 20nm. The dominant wavelength (631nm) defines the perceived red color. This spectrum is stable over the operating current and temperature range, which is important for color-critical applications.

5. Mechanical and Package Information

5.1 Package Dimensions

The LED is housed in an industry-standard 1206 surface-mount package. Key dimensions (in millimeters) include a body length of approximately 3.2mm, a width of 1.6mm, and a height of 1.1mm. All dimensional tolerances are typically ±0.10mm unless otherwise specified. The package features two anode/cathode terminals for soldering.

5.2 Polarity Identification

The cathode is typically marked, often by a green tint on the corresponding side of the package or a notch in the plastic body. Correct polarity orientation is essential during PCB layout and assembly.

5.3 Suggested Soldering Pad Layout

A recommended land pattern (solder pad design) is provided to ensure proper solder joint formation, mechanical stability, and heat dissipation during reflow. Adhering to this layout helps prevent tombstoning (component standing up on one end) and ensures reliable electrical connection.

6. Soldering and Assembly Guidelines

6.1 Reflow Soldering Profile

The LED is compatible with infrared (IR) reflow soldering processes. A suggested profile is provided, compliant with JEDEC standards for Pb-free (lead-free) assembly. Key parameters include:

• Pre-heat: 150-200°C for a maximum of 120 seconds to gradually heat the board and components, activating the flux and minimizing thermal shock.
• Peak Temperature: Maximum of 260°C.
• Time Above Liquidus: The device should be exposed to the peak temperature for a maximum of 10 seconds. Reflow should be performed a maximum of two times.

The profile must be characterized for the specific PCB design, components, solder paste, and oven used.

6.2 Hand Soldering

If hand soldering is necessary, use a temperature-controlled soldering iron set to a maximum of 300°C. The soldering time per lead should not exceed 3 seconds, and this should be done only once to prevent thermal damage to the plastic package and the semiconductor die.

6.3 Cleaning

If cleaning is required after soldering, only use specified solvents. Immersing the LED in ethyl alcohol or isopropyl alcohol at room temperature for less than one minute is acceptable. Do not use unspecified chemical liquids as they may damage the epoxy lens or package.

6.4 Storage and Handling

• ESD (Electrostatic Discharge) Sensitivity: LEDs are sensitive to ESD. Proper ESD precautions must be taken during handling, including the use of grounded wrist straps, anti-static mats, and grounded equipment.
• Moisture Sensitivity: The package is moisture-sensitive. When stored in its original sealed moisture-proof bag with desiccant, it has a shelf life of one year at ≤30°C and ≤90% RH. Once the bag is opened, components should be stored at ≤30°C and ≤60% RH and ideally reflowed within one week. For longer storage outside the original bag, use a sealed container with desiccant. Components stored open for more than a week should be baked at approximately 60°C for at least 20 hours before soldering to remove absorbed moisture and prevent "popcorning" during reflow.

7. Packaging and Ordering

The LEDs are supplied in industry-standard packaging for automated assembly.

• Tape and Reel: Components are packaged in 8mm wide embossed carrier tape on 7-inch (178mm) diameter reels.
• Quantity per Reel: 4000 pieces.
• Minimum Order Quantity (MOQ): 500 pieces for remainder quantities.
• Packaging Standard: Complies with ANSI/EIA-481 specifications. Empty pockets in the tape are sealed with a top cover tape.

8. Application Notes and Design Considerations

8.1 Typical Application Circuits

LEDs are current-driven devices. The most reliable drive method is to use a series current-limiting resistor for each LED, especially when connecting multiple LEDs in parallel. This compensates for the natural variation in forward voltage (V_F) from one LED to another, ensuring uniform current and therefore uniform brightness across all devices in the array. Driving LEDs with a constant current source provides the most stable optical output.

8.2 Thermal Management

Although power dissipation is relatively low (62.5mW max), proper thermal design extends LED life and maintains brightness. Ensure the PCB has adequate copper area connected to the LED pads to act as a heat sink, especially when operating at or near the maximum DC current. Avoid operating in ambient temperatures at the upper limit of the range for extended periods.

8.3 Application Scope

This LED is suitable for general electronic equipment requiring status indicators, backlighting, or decorative lighting. This includes applications in consumer electronics, office equipment, communication devices, and household appliances. It is not specifically designed or qualified for applications where failure could jeopardize life or safety (e.g., aviation, medical life-support, critical traffic control). For such applications, consultation with the manufacturer for specially qualified components is necessary.

9. Technology Comparison and Differentiation

This LED uses AlInGaP technology, which offers distinct advantages for red/orange/yellow emission compared to other technologies like AllnGaP on a absorbing substrate or older GaAsP LEDs.

• High Efficiency & Brightness: AlInGaP provides higher luminous efficacy (more light output per electrical watt) than traditional technologies, enabling the high brightness (up to 180mcd) in a small package.
• Color Stability: The color point (dominant wavelength) of AlInGaP LEDs is more stable over operating current and temperature ranges and over the device's lifetime compared to some alternatives.
• Wide Viewing Angle: The 130° viewing angle with a water-clear lens offers broad, even illumination compared to focused or narrow-angle lenses.
• Surface-Mount Compatibility: The 1206 package and compatibility with IR reflow represent a modern, manufacturable solution compared to through-hole LEDs.

10. Frequently Asked Questions (FAQ)

10.1 What resistor value should I use?

The series resistor value (R_s) is calculated using Ohm's Law: R_s = (V_supply - V_F) / I_F. Use the maximum V_F from the datasheet (2.4V) to ensure the current does not exceed the desired I_F (e.g., 20mA) under worst-case conditions. For a 5V supply: R_s = (5V - 2.4V) / 0.020A = 130 Ohms. A standard 130Ω or 150Ω resistor would be appropriate.

10.2 Can I drive it with a PWM signal?

Yes, Pulse Width Modulation (PWM) is an excellent method for dimming LEDs. It maintains the LED's color characteristics better than analog (current) dimming. Ensure the PWM frequency is high enough to avoid visible flicker (typically >100Hz) and that the peak current in each pulse does not exceed the absolute maximum rating of 60mA.

10.3 Why is there such a wide range in luminous intensity?

The range (18-180mcd) represents the total spread across all production bins. Individual LEDs are sorted into specific bins (M, N, P, Q, R) with much tighter ranges. You must specify the desired bin when ordering to guarantee the brightness level for your application.

10.4 How long will the LED last?

LED lifetime (often defined as the point where light output degrades to 70% of initial value, L70) is not explicitly stated in this datasheet. Lifetime is heavily dependent on operating conditions, primarily junction temperature and drive current. Operating well below the maximum ratings (e.g., at 15-20mA and with good thermal management) will significantly extend operational life, potentially to tens of thousands of hours.

11. Practical Design and Usage Examples

11.1 Status Indicator Panel

In a multi-status indicator panel for industrial equipment, several of these LEDs (e.g., Bin P or Q for medium-high brightness) can be arranged in a row. Each is driven by a microcontroller GPIO pin through a series resistor (e.g., 150Ω for a 3.3V or 5V system). The wide viewing angle ensures the status is visible from various operator positions. The compatibility with reflow allows the entire board, including LEDs and microcontroller, to be soldered in one pass.

11.2 Backlighting for Membrane Switches

A single LED of Bin R (highest brightness) can be placed adjacent to a translucent membrane switch icon to provide backlighting. The diffuse, wide-angle light from the water-clear lens helps evenly illuminate the icon. The low profile (1.1mm height) allows it to fit into slim device designs.

12. Technical Principle Introduction

Light emission in this LED is based on electroluminescence in a semiconductor p-n junction made of AlInGaP. When a forward voltage is applied, electrons from the n-type region and holes from the p-type region are injected into the active region (the junction). When electrons and holes recombine, they release energy in the form of photons (light). The specific composition of the Aluminum, Indium, Gallium, and Phosphide in the crystal lattice determines the bandgap energy, which directly defines the wavelength (color) of the emitted light—in this case, red at approximately 639nm. The "Water Clear" epoxy lens encapsulates the chip, providing mechanical protection, shaping the light output pattern, and enhancing light extraction from the semiconductor material.

13. Technology Trends and Developments

The general trend in SMD indicator LEDs like this one is towards even higher efficiency (more lumens per watt), which allows for the same brightness at lower drive currents, reducing power consumption and heat generation. There is also a continuous drive for miniaturization while maintaining or improving optical performance. Furthermore, improvements in package materials and manufacturing processes enhance reliability and compatibility with increasingly demanding soldering profiles required for lead-free assembly. Color consistency and tighter binning tolerances are also areas of ongoing development to meet the needs of applications requiring precise color matching.