White LED LTW-008ZDCG Datasheet - InGaN White - 20mA - 3.6V - 120mW - Technical Documentation

1. Product Overview

Bu belge, yüzey montaj teknolojisi (SMT) uygulamaları için özel olarak tasarlanmış yüksek parlaklıklı beyaz ışık yayan bir diyotun (LED) teknik özelliklerini ayrıntılı olarak açıklamaktadır. Cihaz, beyaz ışık üretmek için indiyum galyum nitrür (InGaN) yarı iletken malzemesini kullanır ve sarı bir lens ile filtre edilir. 8 milimetrelik kaset ambalajında sunulur ve 7 inç çapındaki makaralarda tedarik edilir, otomatik yüzey montaj ekipmanlarıyla tam uyumludur. Ürün, çevre dostu bir ürün olarak sınıflandırılmıştır, Zararlı Maddelerin Sınırlandırılması (RoHS) Direktifi'ne uygundur ve kurşunsuz bir ürün olduğunu gösterir. Ana tasarım amacı, kompakt, güvenilir ve tutarlı beyaz aydınlatma gerektiren uygulama ihtiyaçlarını karşılamaktır.

2. In-Depth and Objective Interpretation of Technical Parameters

2.1 Absolute Maximum Ratings

These ratings define the stress limits that may cause permanent damage to the device. Operation under these conditions is not guaranteed.

• Power Dissipation (Pd):120 mW. This is the maximum power that the LED package can dissipate as heat without exceeding its thermal limits.
• Peak Forward Current (I_FP):100 mA. This is the maximum instantaneous forward current allowed, typically specified under pulse conditions (1/10 duty cycle, 0.1ms pulse width) to prevent overheating.
• Direct forward current (I_F):30 mA. This is the recommended maximum continuous forward current to ensure long-term reliable operation.
• Reverse voltage (V_R):5 V. Applying a reverse voltage exceeding this value may cause breakdown and damage the LED junction. Continuous reverse voltage operation is prohibited.
• Operating temperature range (T_opr):-30°C to +85°C. This is the ambient temperature range within which the LED is designed to operate normally.
• Storage temperature range (T_stg):-40°C to +100°C. This is the storage temperature range of the device in a non-operating state.
• Reflow soldering conditions:Can withstand 260°C for 10 seconds, which complies with typical lead-free solder reflow temperature profiles (e.g., J-STD-020D).

2.2 Electrical and Optical Characteristics

These parameters are measured under standard test conditions of Ta=25°C and I_F= 20 mA, unless otherwise specified.

• Luminous intensity (I_V):The range spans from a minimum of 860 mcd to a typical value of 1720 mcd. This measures the perceived power of light emitted in a specific direction. Actual values are binned (see Section 3). Measurements follow the CIE human eye response curve.
• Viewing Angle (2θ_1/2):110 degrees. This is the full angle at which the luminous intensity drops to half of its maximum (on-axis) value. This indicates a relatively wide beam pattern.
• Chromaticity coordinates (x, y):On the CIE 1931 chromaticity diagram, typical values are x=0.295, y=0.280, defining the white point color. The tolerance for these coordinates is ±0.01.
• Forward voltage (V_F):At 20mA, the range is from 2.9V to 3.6V. This is the voltage drop across the LED during operation. Actual values are binned (see Section 3).
• ESD Withstand Voltage:2000V (Human Body Model, HBM). This specifies the device's sensitivity to electrostatic discharge, indicating it has a standard level of protection. It is strongly recommended to take appropriate ESD precautions during handling (such as wearing an anti-static wrist strap, using grounded equipment).

3. Bin System Description

To ensure color and performance consistency in production, LEDs are sorted into different bins based on key parameters.

3.1 Forward Voltage (V_F) Binning

LEDs are sorted based on their I_FThe forward voltage at = 20 mA is classified into bins (V0 to V6). Each bin has a range of 0.1V, from V0 (2.9-3.0V) to V6 (3.5-3.6V). A tolerance of ±0.10V is applied within each bin. This allows designers to select LEDs with closely matched voltage drops for current sharing applications in parallel circuits.

3.2 Luminous Intensity (I_V) Binning

LEDs are sorted based on their I_FThe luminous intensity at = 20 mA is binned (S, T, A, B, C, D). The bin range is from S (860-1000 mcd) to D (1580-1720 mcd). Each bin specifies a tolerance of ±10%. This allows for selection in applications requiring specific brightness levels or brightness uniformity among multiple LEDs.

3.3 Chromaticity Coordinate Binning (Color Region)

The document provides a detailed chromaticity zone table (e.g., A52, A53, BE1, BG3), defining specific quadrilateral or triangular areas on the CIE 1931 chromaticity diagram. Each "chromaticity zone" specifies the permissible (x, y) coordinate boundaries for white light output. This precise binning is crucial for applications where color consistency is paramount, such as backlighting or signage. The measurement tolerance for these coordinates is ±0.01.

4. Performance Curve Analysis

4.1 Relative Intensity vs. Wavelength Relationship

Figure 1 in the datasheet shows the Spectral Power Distribution (SPD) of the emitted light. For a white LED using a blue InGaN chip and yellow phosphor, the curve typically shows a primary peak from the chip in the blue region (approximately 450-460 nm) and a broader peak or hump produced by the phosphor in the yellow/green region (approximately 550-600 nm). The combination of these spectra creates the perception of white light. The full width of the curve extends roughly from 400 nm to 750 nm, covering the visible spectrum.

5. Mechanical and Packaging Information

5.1 Package Dimensions and Tolerances

This LED conforms to the EIA standard SMD package outline. All critical dimensions are provided in millimeters, with a standard tolerance of ±0.05 mm unless otherwise specified. Key mechanical definitions include:

• Distance A:The vertical distance between the bottom of the pad and the reflector. The minimum value is 0.05mm.
• Tolerance B:The alignment tolerance between the left and right pads. The maximum value is 0.03mm.
• Distance C:Lateral distance between the pad and the reflector wall. The minimum value is 0.05mm.

These dimensions are crucial for PCB pad design and ensuring the formation of good solder joints and light extraction.

5.2 Tape and Reel Packaging Dimensions

Detailed drawings specify carrier tape dimensions (pocket size, pitch, etc.) and reel dimensions (7-inch diameter). Packaging follows the EIA-481-1-B standard. Key considerations include: 2000 pieces per reel, a maximum of two consecutive missing components allowed, and specified leader/trailer tape lengths (minimum 20 cm at the start, minimum 50 cm at the end).

6. Soldering and Assembly Guide

6.1 Reflow Soldering Temperature Profile

This LED is compatible with infrared (IR) and vapor phase reflow soldering processes. It references the recommended lead-free reflow soldering temperature profile compliant with J-STD-020D. The key parameter is that the device can withstand a peak temperature of 260°C for 10 seconds. Following the recommended heating, soaking, and cooling rates is crucial to prevent thermal shock and ensure reliable solder joints.

6.2 Cleaning

If post-soldering cleaning is required, only specific chemicals should be used to avoid damaging the LED package. The datasheet recommends immersion in ethanol or isopropyl alcohol at room temperature for no more than one minute. The use of unspecified chemical liquids is prohibited.

6.3 Storage and Moisture Sensitivity

According to JEDEC J-STD-020, the Moisture Sensitivity Level (MSL) for this product is Level 3.

• Sealed Packaging:Store at ≤30°C and ≤90% RH. Shelf life is one year when stored in the original moisture barrier bag with desiccant.
• Opened package:Store at ≤30°C and ≤60% RH. Components must be soldered within 168 hours (7 days) after exposure to the environment.
• Baking:如果湿度指示卡变粉红色（表明RH >10%）或超出168小时车间寿命，建议在重新密封或使用前，在60°C下烘烤至少48小时。

7. Application Recommendations

7.1 Typical Application Scenarios

This white SMD LED is suitable for various applications requiring compact and efficient white lighting, including but not limited to:

• Status indicators and backlighting for consumer electronics (e.g., home appliances, audio equipment).
• Panel indicator lights and switch backlighting in industrial control systems.
• General illumination in portable devices.
• Decorative lighting and signage.

Important Note:The datasheet clearly states that these LEDs are suitable for general electronic equipment. For applications with special reliability requirements or where failure could endanger life or health (aviation, medical equipment, security systems), consult the manufacturer before design adoption.

7.2 Design Considerations

• Current Limiting:Always use a series current-limiting resistor or a constant-current drive circuit. Do not connect directly to a voltage source. Operate at or below the recommended 30 mA DC forward current.
• Thermal Management:Ensure the PCB provides sufficient heat dissipation, especially when operating under high current or high ambient temperatures, to stay within the 120 mW power consumption limit.
• ESD Protection:Implement standard ESD handling procedures during assembly. If the LED is in an exposed location, consider adding Transient Voltage Suppression (TVS) diodes or other protective measures on the circuit board.
• Optical Design:A 110-degree viewing angle provides a wide beam. Secondary optics (lenses) may be required for more focused light.

8. Technical Comparison and Differentiation

Although this individual datasheet does not provide a direct side-by-side comparison with other models, the key differentiating features of this LED can be inferred:

• Wide viewing angle (110°):Compared to LEDs with a narrower viewing angle, it provides broader illumination, suitable for area lighting rather than spotlighting.
• Detailed Binning:Extensive V_F, I_Vand chromaticity binning provide high consistency for applications requiring performance matching across multiple units.
• Sturdy Packaging:Compatible with automated placement and standard lead-free reflow soldering temperature profiles (peak 260°C), facilitating high-volume, reliable manufacturing.
• InGaN Technology:Provides typical high-efficiency white light generation capability for modern high-brightness LED designs.

9. Frequently Asked Questions (Based on Technical Parameters)

9.1 What is the difference between Peak Forward Current (100mA) and DC Forward Current (30mA)?

DC forward current (30mA) is the maximum current for continuous, steady-state operation. Peak forward current (100mA) is a higher current that the LED can only withstand under very short pulses (0.1ms width) and low duty cycle (10%). This is useful for applications such as multiplexing or PWM dimming, where brief high-current pulses can achieve higher instantaneous brightness without overheating the LED. Sustained operation beyond the DC current rating will lead to overheating and rapid performance degradation.

9.2 How to interpret the Chromaticity Coordinates (x=0.295, y=0.280)?

These coordinates plot the color of the white light on the CIE 1931 chromaticity diagram. This specific point typically corresponds to a "cool white" or "daylight white" color temperature, usually in the 6000K-7000K range. A tolerance of ±0.01 defines a small area on the chart; the color of any individual LED from this batch should fall within this area to ensure color uniformity.

9.3 Why are the storage conditions so strict (MSL 3)? What happens if the 168-hour floor life is exceeded?

SMD packages absorb moisture from the air. During the high-temperature reflow soldering process, this trapped moisture rapidly turns to steam, causing delamination, cracking, or "popcorn" effect inside the plastic package, which can damage the LED. The MSL 3 and 168-hour limit define the safe exposure time for the package's specific moisture absorption rate. If exceeded, baking (60°C, 48 hours) can remove the absorbed moisture, restoring the component to a dry state suitable for reflow.

10. Design Use Cases

10.1 Design a Status Indicator Panel

Scenario:Design a control panel with 10 uniform white LED status indicators.

Design Steps:

1. Current setting:Select an operating point, e.g., I_F= 20 mA, to achieve reliable operation and directly use the binning data from the datasheet.
2. Voltage calculation:Assuming the power supply voltage is 5V (V_CC). From the same V_FSelect LED in the gear, for example V3 (3.2-3.3V). Use the typical value (3.25V) for calculation. The required series resistance R = (V_CC- V_F) / I_F= (5 - 3.25) / 0.020 = 87.5 Ω. A standard 91 Ω or 82 Ω resistor can be used to slightly adjust the current.
3. Brightness uniformity:Specify from the same I_Vbin LEDs (e.g., Bin C: 1440-1580 mcd) to ensure all indicators have similar perceived brightness.
4. Uniformity of Color:Specify LEDs from the same color bin (e.g., A63) to ensure all lights emit the exact same white hue, which is crucial for aesthetic consistency.
5. PCB Layout:Follow the pad dimensions recommended in the datasheet. Ensure the pad design adheres to the minimum distance (A, C) from the LED body/reflector to prevent short circuits and allow for proper solder fillet formation.
6. Assembly:Use the recommended infrared reflow soldering temperature profile. Keep the LEDs in the sealed bag until ready for assembly. If the bag has been opened, complete the soldering of all 10 LEDs within 168 hours.

11. Brief Introduction to Working Principle

This white LED operates based on the principle of electroluminescence in semiconductors. Its core is a chip made of indium gallium nitride (InGaN). When a forward voltage (typically 2.9-3.6V) is applied, electrons and holes recombine at its bandgap, emitting blue light. To produce white light, the blue-emitting chip is coated with a layer of cerium-doped yttrium aluminum garnet (YAG:Ce) phosphor. A portion of the high-energy blue photons from the chip are absorbed by the phosphor and then re-emitted as lower-energy yellow light through a process called photoluminescence. The remaining unabsorbed blue light mixes with the emitted yellow light, and the human eye perceives this combination as white light. The yellow lens further diffuses and shapes the final light output.

12. Technical Trends

The technology described in this datasheet represents a mature and widely adopted method for generating white light with LEDs. In the broader LED industry, ongoing key trends related to such components include:

• Efficiency Improvement (lm/W):Continuous improvements in InGaN chip design, phosphor efficiency, and packaging architecture have led to higher luminous efficacy, meaning more light output can be generated from the same electrical input power.
• Color Quality Improvement:Develop multi-phosphor mixtures (e.g., adding red phosphor) to improve the Color Rendering Index (CRI), providing more accurate and pleasing color reproduction under LED light.
• Miniaturization:The drive for smaller devices in consumer electronics prompts the adoption of smaller LED package sizes while maintaining or increasing light output.
• Higher Reliability and Lifespan:Advancements in materials (epoxy resin, phosphor, substrate) and thermal management design are extending the operational lifespan (L70, L90) of LEDs, reducing long-term maintenance costs.
• Smart and Connected Lighting:Although it is a fundamental component, the entire ecosystem is evolving towards integrating LEDs as an indispensable part of smart systems, typically requiring compatible drivers to enable dimming, color adjustment, and connectivity functions.