SMD LED Datasheet - Red Diffused AlInGaP - 120° Viewing Angle - 2.0V Typ - 72mW Power - English Technical Document

1. Product Overview

This document details the specifications for a surface-mount device (SMD) LED utilizing a diffused lens and an AlInGaP (Aluminum Indium Gallium Phosphide) light source, emitting red light. These LEDs are engineered for automated printed circuit board (PCB) assembly processes, making them ideal for applications where space is at a premium and high-volume production is required.

1.1 Core Advantages and Target Markets

The primary advantages of this component include its compatibility with automated pick-and-place equipment and infrared (IR) reflow soldering processes, which are standard in modern electronics manufacturing. It is packaged on 8mm tape wound onto 7-inch diameter reels, facilitating efficient handling and assembly. The device is RoHS compliant, ensuring it meets environmental regulations. Its target applications span a broad range of consumer and industrial electronics, including but not limited to telecommunications equipment (e.g., cordless and cellular phones), office automation devices (e.g., notebook computers), network systems, home appliances, and indoor signage. It is commonly used for status indication, symbolic illumination, and front panel backlighting.

2. In-Depth Technical Parameter Analysis

2.1 Absolute Maximum Ratings

Operating the device beyond these limits may cause permanent damage. Key ratings at an ambient temperature (Ta) of 25°C are:

• Power Dissipation (Pd): 72 mW. This is the maximum power the LED package can safely dissipate as heat.
• Continuous Forward Current (IF): 30 mA DC. The maximum steady-state current for reliable operation.
• Peak Forward Current: 80 mA, permissible only under pulsed conditions (1/10 duty cycle, 0.1ms pulse width).
• Operating Temperature Range: -40°C to +85°C.
• Storage Temperature Range: -40°C to +100°C.

2.2 Electrical and Optical Characteristics

Typical performance is measured at Ta=25°C and a forward current (IF) of 20 mA, unless otherwise stated.

• Luminous Intensity (Iv): Ranges from a minimum of 90.0 mcd to a maximum of 280.0 mcd. The actual value is determined by the bin code (see Section 3).
• Viewing Angle (2θ½): 120 degrees (typical). This wide viewing angle, characteristic of a diffused lens, ensures light is spread over a broad area rather than being highly directional.
• Dominant Wavelength (λd): 631 nm (typical), with a tolerance of ±1 nm. This parameter defines the perceived color (red). The peak emission wavelength (λp) is typically 639 nm.
• Spectral Line Half-Width (Δλ): Approximately 15 nm, indicating the spectral purity of the red light.
• Forward Voltage (VF): 2.0 V (typical), with a maximum of 2.4 V at 20 mA. The tolerance is ±0.1 V.
• Reverse Current (IR): Maximum of 10 µA at a reverse voltage (VR) of 5V. It is critical to note that this device is not designed for operation under reverse bias; this test condition is for characterization only.

3. Binning System Explanation

To ensure consistency in brightness across production batches, the LEDs are sorted into bins based on their luminous intensity measured at 20 mA.

3.1 Luminous Intensity Binning

The bin codes and their corresponding intensity ranges are as follows. Tolerance within each bin is ±11%.

• Q2: 90.0 – 112.0 mcd
• R1: 112.0 – 140.0 mcd
• R2: 140.0 – 180.0 mcd
• S1: 180.0 – 224.0 mcd
• S2: 224.0 – 280.0 mcd

This system allows designers to select the appropriate brightness grade for their specific application, balancing performance and cost.

4. Performance Curve Analysis

While specific graphical data is referenced in the datasheet, the typical relationships can be described:

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

The AlInGaP material exhibits a characteristic I-V curve where the forward voltage increases logarithmically with current. The typical Vf of 2.0V at 20mA is a key parameter for driver circuit design.

4.2 Luminous Intensity vs. Forward Current

The light output (luminous intensity) is approximately proportional to the forward current within the recommended operating range. Exceeding the maximum DC current will not yield proportional increases in light and risks damaging the device.

4.3 Spectral Distribution

The emission spectrum centers around 631 nm (dominant wavelength) with a typical half-width of 15 nm, producing a saturated red color.

5. Mechanical and Package Information

5.1 Package Dimensions and Polarity

The device conforms to a standard EIA package footprint. Detailed dimensional drawings are provided in the datasheet, with all dimensions in millimeters and a general tolerance of ±0.2 mm. The cathode is typically identified by a marking on the package or a specific pad geometry on the tape. The recommended PCB attachment pad layout for infrared or vapor phase reflow soldering is also specified to ensure proper solder joint formation and mechanical stability.

5.2 Tape and Reel Packaging

The LEDs are supplied in embossed carrier tape with a protective cover tape, wound onto 7-inch (178 mm) diameter reels. Each reel contains 2000 pieces. The packaging follows ANSI/EIA 481 specifications. Key notes include: empty component pockets are sealed, and a maximum of two consecutive missing components ("lamps") is allowed per reel.

6. Soldering and Assembly Guidelines

6.1 IR Reflow Soldering Profile

A suggested temperature profile compliant with J-STD-020B for lead-free (Pb-free) processes is provided. Critical parameters include:

• Pre-heat: 150°C to 200°C.
• Pre-heat Time: Maximum 120 seconds.
• Peak Temperature: Maximum 260°C.
• Time Above Liquidus: Recommended to follow solder paste manufacturer specifications and JEDEC guidelines.

Because board design, component density, and oven characteristics vary, this profile should be used as a generic target and fine-tuned for the specific assembly line.

6.2 Manual Soldering (Soldering Iron)

If manual rework is necessary, the iron tip temperature should not exceed 300°C, and contact time should be limited to a maximum of 3 seconds per solder joint. Re-soldering should be performed only once.

7. Storage and Handling Cautions

7.1 Storage Conditions

• Sealed Package: Store at ≤ 30°C and ≤ 70% Relative Humidity (RH). The shelf life is one year when stored in the original moisture-proof bag with desiccant.
• Opened Package: Components exposed to ambient air should be stored at ≤ 30°C and ≤ 60% RH. It is strongly recommended to complete the IR reflow process within 168 hours (7 days) of opening the bag.
• Extended Storage (Out of Bag): For storage beyond 168 hours, place components in a sealed container with desiccant or in a nitrogen desiccator. Components stored out of bag for more than 168 hours require a bake-out at approximately 60°C for at least 48 hours before soldering to remove absorbed moisture and prevent "popcorning" during reflow.

7.2 Cleaning

If cleaning after soldering is required, use only alcohol-based solvents such as isopropyl alcohol (IPA) or ethyl alcohol. Immerse the LED for less than one minute at normal room temperature. Do not use unspecified chemical cleaners as they may damage the epoxy lens or package.

8. Application Design Considerations

8.1 Drive Circuit Design

LEDs are current-driven devices. To ensure uniform brightness when driving multiple LEDs, it is essential to use a current-limiting resistor in series with each LED. Connecting LEDs directly in parallel without individual resistors is not recommended, as slight variations in forward voltage (Vf) between devices can cause significant current imbalance, leading to uneven brightness and potential over-current in some LEDs. The datasheet illustrates the recommended circuit (Circuit A) with a series resistor for each LED.

8.2 Thermal Management

While the power dissipation is relatively low (72 mW), maintaining the LED junction temperature within the specified range is crucial for long-term reliability and stable light output. Ensure adequate PCB copper area or thermal vias are used if the LED is operated at or near its maximum current rating, especially in high ambient temperature environments.

8.3 Application Scope and Limitations

This component is intended for use in standard electronic equipment. It is not designed or qualified for applications where high reliability is critical to safety, such as in aviation, transportation control, medical life-support systems, or safety devices. For such applications, consultation with the manufacturer for specifically qualified components is mandatory.

9. Technical Comparison and Differentiation

Compared to older LED technologies, AlInGaP LEDs offer higher efficiency and better color saturation for red and amber colors. The diffused lens package provides a wide 120-degree viewing angle, which is advantageous for applications requiring broad area illumination or visibility from multiple angles, as opposed to narrow-angle LEDs used for focused beams. The compatibility with standard IR reflow processes differentiates it from LEDs that require manual soldering or wave soldering, enabling cost-effective, high-speed assembly.

10. Frequently Asked Questions (Based on Technical Parameters)

10.1 What resistor value should I use for a 5V supply?

Using Ohm's Law (R = (Vsupply - Vf_LED) / I_LED) and assuming a typical Vf of 2.0V and a desired current of 20 mA: R = (5V - 2.0V) / 0.020A = 150 Ohms. A standard 150 Ω resistor would be suitable. Always calculate using the maximum possible Vf (2.4V) to ensure the current does not exceed the maximum rating under worst-case conditions.

10.2 Can I pulse this LED at higher currents for brighter flashes?

Yes, the datasheet specifies a peak forward current of 80 mA under pulsed conditions (1/10 duty cycle, 0.1ms pulse width). This can be used to achieve higher instantaneous brightness for strobe or indicator applications, but the average current over time must not cause the power dissipation to exceed 72 mW.

10.3 How do I interpret the bin code on my order?

The bin code (e.g., R2, S1) corresponds to the luminous intensity range. When ordering, specifying a bin code ensures you receive LEDs with brightness within that specific range, which is important for consistency in your product's appearance.

11. Practical Design and Usage Example

11.1 Designing a Status Indicator Panel

Consider a router with multiple status LEDs. Using this SMD LED, the designer would:

1. Select the appropriate brightness bin (e.g., R2 for medium brightness) based on the required visibility.
2. Design the PCB layout using the recommended pad dimensions to ensure proper soldering and alignment.
3. For each LED, calculate and place a series current-limiting resistor based on the system's supply voltage (e.g., 3.3V or 5V).
4. Follow the recommended IR reflow profile during assembly.
5. If the assembly board needs cleaning, use only isopropyl alcohol.

This approach ensures reliable, uniform, and long-lasting indicator lights.

12. Operational Principle

This LED is based on AlInGaP semiconductor material. When a forward voltage exceeding the diode's turn-on threshold is applied, electrons and holes recombine in the active region of the semiconductor, releasing energy in the form of photons (light). The specific composition of the AlInGaP layers determines the bandgap energy, which in turn defines the wavelength (color) of the emitted light—in this case, red at approximately 631 nm. The diffused epoxy lens contains scattering particles that randomize the direction of the emitted photons, creating a wide, uniform viewing angle instead of a narrow beam.

13. Technology Trends

The general trend in SMD LED technology continues toward higher luminous efficacy (more light output per watt of electrical input), improved color rendering, and smaller package sizes enabling higher density designs. There is also a focus on enhancing reliability under higher temperature and current operating conditions. The widespread adoption of lead-free soldering and RoHS compliance, as seen with this component, remains a standard requirement in global electronics manufacturing.