Top View LED 67-21 Series - P-LCC-2 Package - White - 1.75-2.35V - 120mW - English Technical Document

1. Product Overview

The 67-21 series represents a family of Top View LEDs designed for indicator and backlighting applications. These components are housed in a compact P-LCC-2 (Plastic Leaded Chip Carrier) package with a white body and a colorless clear window, which contributes to a wide viewing angle. The primary design goal is to optimize light coupling through an internal reflector, making these LEDs particularly suitable for use with light pipes. Their low forward current requirement makes them an excellent choice for power-sensitive applications such as portable electronic devices, automotive dashboards, and telecommunications equipment.

1.1 Core Advantages and Target Market

The key advantages of this LED series include a wide viewing angle of typically 120 degrees, compatibility with automated placement equipment and vapor-phase reflow soldering processes, and availability on 8mm tape and reel for high-volume manufacturing. The product is Pb-free and compliant with RoHS regulations. The target markets are diverse, encompassing automotive (dashboard and switch backlighting), telecommunications (phone and fax indicators), general flat backlighting for LCDs and symbols, and any general-purpose indicator application where reliable, low-power illumination is required.

2. In-Depth Technical Parameter Analysis

This section provides a detailed breakdown of the critical electrical, optical, and thermal parameters that define the performance boundaries and operating conditions of the LED.

2.1 Absolute Maximum Ratings

The Absolute Maximum Ratings define the limits beyond which permanent damage to the device may occur. These are not recommended operating conditions. The maximum reverse voltage (VR) is 5V. The continuous forward current (IF) should not exceed 50mA, while a peak forward current (IFP) of 100mA is permissible under pulsed conditions (1/10 duty cycle at 1kHz). The maximum power dissipation (Pd) is 120mW. The device can withstand an electrostatic discharge (ESD) of 2000V using the Human Body Model (HBM). The operating temperature range (Topr) is from -40°C to +85°C, and the storage temperature range (Tstg) is from -40°C to +90°C. Soldering temperatures are specified for both reflow (260°C for 10 seconds) and hand soldering (350°C for 3 seconds).

2.2 Electro-Optical Characteristics

The Electro-Optical Characteristics are measured at a standard test condition of Ta=25°C and IF=20mA. The luminous intensity (Iv) has a typical range, with a minimum of 180 mcd and a maximum of 565 mcd, subject to a tolerance of ±11%. The dominant wavelength (λd) for the provided data is in the red spectrum, ranging from 621nm to 631nm, with a tolerance of ±1nm. The forward voltage (VF) ranges from 1.75V to 2.35V, with a tolerance of ±0.1V. The viewing angle (2θ1/2) is typically 120 degrees. The reverse current (IR) is a maximum of 10µA at VR=5V.

3. Binning System Explanation

To ensure consistency in brightness, color, and electrical characteristics, the LEDs are sorted into bins. This allows designers to select parts that meet specific application requirements.

3.1 Luminous Intensity Binning

Luminous intensity is categorized into five bins: S1 (180-225 mcd), S2 (225-285 mcd), T1 (285-360 mcd), T2 (360-450 mcd), and U1 (450-565 mcd). All measurements are at IF=20mA.

3.2 Dominant Wavelength Binning

The dominant wavelength is grouped under code 'F', with two sub-bins: FF1 (621-626 nm) and FF2 (626-631 nm).

3.3 Forward Voltage Binning

Forward voltage is grouped under code 'B', with three sub-bins: 0 (1.75-1.95V), 1 (1.95-2.15V), and 2 (2.15-2.35V).

4. Performance Curve Analysis

Graphical data provides insight into the LED's behavior under varying conditions, which is crucial for robust circuit design.

4.1 Forward Current Derating Curve

A curve shows the maximum allowable forward current decreasing as the ambient temperature increases above 25°C. This is critical for thermal management and ensuring long-term reliability.

4.2 Forward Current vs. Forward Voltage

This IV characteristic curve shows the relationship between forward current and forward voltage at 25°C. It is non-linear, typical of a diode, and is essential for designing the current-limiting circuitry.

4.3 Relative Luminous Intensity vs. Forward Current

This curve demonstrates how light output increases with forward current. It helps designers balance brightness requirements against power consumption and device stress.

4.4 Relative Luminous Intensity vs. Ambient Temperature

This graph shows the reduction in light output as the junction temperature rises, highlighting the importance of heat dissipation in maintaining consistent brightness.

4.5 Spectrum Distribution

The spectral output graph shows a peak wavelength around 632nm, confirming the red color emission, with a typical spectral bandwidth (Δλ) of 20nm.

4.6 Radiation Diagram

A polar plot illustrates the spatial distribution of light intensity, confirming the wide 120-degree viewing angle. The intensity is relatively uniform across a broad central region.

5. Mechanical and Packaging Information

5.1 Package Dimensions

The technical drawing specifies the physical dimensions of the P-LCC-2 package. Critical measurements include the overall length, width, and height, lead spacing, and the size of the lens aperture. All unspecified tolerances are ±0.1mm.

5.2 Polarity Identification

The cathode is typically identified by a notch or a green marking on the package. Correct polarity must be observed during assembly to prevent device failure.

6. Soldering and Assembly Guidelines

6.1 Reflow Soldering Parameters

The LED is suitable for vapor-phase reflow soldering. The maximum recommended peak temperature is 260°C, and the device should not be exposed to temperatures above this for more than 10 seconds. A standard reflow profile for Pb-free solders is applicable.

6.2 Hand Soldering

If hand soldering is necessary, the iron tip temperature should not exceed 350°C, and the contact time per lead should be limited to 3 seconds or less.

6.3 Storage Conditions

Devices are packaged in moisture-resistant barrier bags with desiccant to prevent moisture absorption. Once the bag is opened, components should be used within a specified time frame (not explicitly stated in the provided PDF but is standard practice) or baked according to MSL (Moisture Sensitivity Level) guidelines before reflow to avoid \"popcorn\" effect damage during soldering.

7. Packaging and Ordering Information

7.1 Tape and Reel Specifications

The LEDs are supplied on 8mm carrier tape. The reel dimensions and the pocket pitch of the carrier tape are detailed in the drawings. Each reel contains 2000 pieces.

7.2 Label Explanation

The reel label contains several codes: CAT (Luminous Intensity Rank), HUE (Dominant Wavelength Rank), and REF (Forward Voltage Rank). These correspond directly to the binning information, allowing traceability and ensuring the correct product variant is used.

8. Application Recommendations

8.1 Typical Application Scenarios

• Automotive: Backlighting for instrument clusters, dashboard switches, and control panels.
• Telecommunications: Status indicators on phones, fax machines, and networking equipment.
• Consumer Electronics: Backlighting for membrane switches, keypads, and LCD panels in appliances.
• General Indication: Power status, mode selection, and alert indicators in a wide range of electronic devices.

8.2 Design Considerations

• Current Limiting: Always use a series resistor or constant current driver to limit the forward current to the desired value (e.g., 20mA for typical brightness). Calculate the resistor value using R = (Vsupply - Vf) / If.
• Thermal Management: For continuous operation at high ambient temperatures or near maximum current, consider PCB layout for heat dissipation. Avoid placing LEDs near other heat sources.
• Light Pipe Coupling: The wide viewing angle and package design are optimized for light pipes. Ensure proper alignment and minimal gap between the LED and the light pipe entry point for efficient light coupling.
• ESD Protection: Although rated for 2000V HBM, implement standard ESD precautions during handling and assembly.

9. Reliability Testing

The product reliability is validated through a series of tests conducted with a 90% confidence level and an LTPD (Lot Tolerance Percent Defective) of 10%. Key tests include:

• Reflow Soldering: Withstanding 260°C ±5°C for a maximum of 10 seconds.
• Temperature Cycling: 300 cycles between -40°C and +100°C.
• Thermal Shock: Rapid transitions between -40°C and +100°C.

These tests ensure the device's robustness in typical manufacturing and operational environments.

10. Frequently Asked Questions (FAQs)

10.1 What is the purpose of the binning codes (CAT, HUE, REF)?

The binning codes are used to categorize LEDs based on their measured luminous intensity (CAT), dominant wavelength/color (HUE), and forward voltage (REF). This allows manufacturers and designers to select components with tightly controlled characteristics, ensuring consistency in the brightness and color of the final product, especially when multiple LEDs are used in an array.

10.2 Can I drive this LED without a current-limiting resistor?

No. An LED is a current-driven device. Connecting it directly to a voltage source higher than its forward voltage will cause excessive current to flow, potentially destroying the LED instantly due to thermal runaway. A series resistor or active constant-current circuit is mandatory.

10.3 How does ambient temperature affect performance?

As ambient temperature increases, the LED's junction temperature rises. This leads to a decrease in luminous efficiency (lower light output for the same current) and a slight decrease in the forward voltage. The derating curve specifies how the maximum allowable current must be reduced at higher temperatures to prevent overheating and premature failure.

10.4 Is this LED suitable for outdoor applications?

The operating temperature range of -40°C to +85°C makes it suitable for many outdoor and automotive environments. However, for direct outdoor exposure, additional design considerations are necessary, such as protection from UV radiation (which can yellow the epoxy over time), moisture sealing of the entire assembly, and robust thermal management under direct sunlight.

11. Practical Design Case Study

Scenario: Designing a backlit membrane switch panel for an industrial control unit requiring 10 red indicator LEDs. The panel operates from a 5V supply in an environment up to 60°C.

Design Steps:

1. Current Selection: Choose a forward current of 20mA for a good balance of brightness and longevity.
2. Resistor Calculation: Using the maximum forward voltage from bin B2 (2.35V) for worst-case design: R = (5V - 2.35V) / 0.020A = 132.5Ω. A standard 130Ω or 150Ω resistor can be used. The power rating of the resistor should be at least (5V-2.35V)*0.02A = 0.053W, so a standard 1/8W (0.125W) resistor is sufficient.
3. Thermal Check: At 60°C ambient, consult the derating curve. The maximum allowable current is reduced. Ensure 20mA is still within the safe operating area at 60°C. If not, reduce the drive current or improve heat sinking.
4. Binning Selection: For uniform appearance, specify tight bins for HUE (wavelength) and CAT (intensity), e.g., HUE: FF1 and CAT: T1 or T2, depending on the required brightness level.
5. Layout: Place LEDs evenly. If using a light guide, follow mechanical drawings for precise alignment. Ensure PCB pads match the recommended footprint.

12. Technical Principle Introduction

The LED operates on the principle of electroluminescence in a semiconductor material. For the red variant described, the chip material is AlGaInP (Aluminum Gallium Indium Phosphide). When a forward voltage is applied across the p-n junction, electrons and holes are injected into the active region where they recombine. This recombination process releases energy in the form of photons (light). The specific composition of the AlGaInP alloy determines the bandgap energy, which in turn defines the wavelength (color) of the emitted light—in this case, in the red spectrum (~632nm peak). The P-LCC-2 package encapsulates the semiconductor die, provides mechanical protection, houses the internal reflector to shape the light output, and forms the electrical leads for connection.

13. Industry Trends and Developments

The market for indicator LEDs like the 67-21 series continues to evolve. Key trends include:

• Increased Efficiency: Ongoing material science and chip design improvements lead to higher luminous efficacy (more light output per watt of electrical input), allowing for lower power consumption or brighter indicators.
• Miniaturization: While the P-LCC-2 is a standard package, there is a constant drive for smaller footprints (e.g., chip-scale packages) to save space on increasingly dense PCBs, especially in portable devices.
• Enhanced Reliability: Demands for longer lifetimes and operation in harsher environments (higher temperature, humidity) push improvements in packaging materials, die attach methods, and phosphor technology (for white LEDs).
• Smart Integration: A growing trend is the integration of control circuitry (like constant current drivers or PWM controllers) within the LED package itself, simplifying external circuit design.
• Broadened Color Gamut and Consistency: Advances in binning technology and phosphor materials enable tighter color control and a wider range of saturated colors, meeting the demands of aesthetic design and color-coded indicators.