White LED RF-WUD191DS-DD Specification - Dimensions 1.6x0.8x0.98mm - Forward Voltage 2.8-3.7V - 111mW Power - Technical Document

1. Product Overview

This document provides a comprehensive technical specification for a high-performance surface-mount white light-emitting diode (LED). The device is designed for modern electronic applications requiring reliable, efficient, and compact illumination solutions.

1.1 Product Positioning and General Description

The LED is a white light source fabricated using a blue semiconductor chip combined with a phosphor coating to achieve broad-spectrum white light emission. Its primary positioning is as a cost-effective, highly reliable component for mass-produced electronic devices. The ultra-compact package dimensions of 1.6mm in length, 0.8mm in width, and 0.98mm in height make it ideal for space-constrained applications. The product is classified as a mass-production item, indicating its maturity and suitability for high-volume manufacturing.

1.2 Core Advantages and Features

The LED offers several distinct advantages that make it a preferred choice for designers:

• Extremely Wide Viewing Angle: With a typical viewing angle (2θ½) of 140 degrees, it provides uniform and broad illumination, eliminating hotspots and ensuring consistent visibility from various perspectives.
• SMT Compatibility: The device is fully compatible with all standard Surface Mount Technology (SMT) assembly and soldering processes, including reflow soldering, facilitating automated, high-speed PCB assembly.
• Robust Environmental Rating: It has a Moisture Sensitivity Level (MSL) of Level 3, which defines specific handling and baking requirements to prevent moisture-induced damage during soldering, enhancing reliability.
• Environmental Compliance: The product is compliant with the Restriction of Hazardous Substances (RoHS) directive, ensuring it meets international environmental standards for electronic components.

1.3 Target Market and Application

This LED is targeted at a wide range of markets within the consumer electronics, industrial control, and instrumentation sectors. Its primary applications include:

• Optical Indicators: Serving as status lights, power indicators, and notification LEDs in devices such as routers, printers, home appliances, and automotive dashboards.
• Switch and Symbol Illumination: Backlighting for buttons, keypads, and panel symbols to enhance user interface visibility in low-light conditions.
• Display Backlighting: Used as auxiliary lighting for small LCD displays or informational panels.
• General Purpose Lighting: Suitable for any application requiring a compact, low-power white light source.

2. In-Depth Technical Parameter Analysis

This section provides a detailed, objective interpretation of the key electrical, optical, and thermal parameters specified for the LED, essential for proper circuit design and performance prediction.

2.1 Photoelectric Characteristics

The photoelectric performance is defined at a standard test current (I_F) of 20mA and an ambient temperature (T_s) of 25°C.

• Luminous Intensity (I_V): This parameter measures the perceived brightness of the LED. It is divided into several bin codes (J20, K10, K20, L10, L20), with values ranging from a minimum of 430 millicandelas (mcd) to a maximum of 1200 mcd. The L20 bin represents the highest brightness tier. The measurement tolerance is ±10%.
• Viewing Angle (2θ½): The full width at half maximum (FWHM) angle is typically 140 degrees. This wide angle is a key feature, ensuring the emitted light is diffuse rather than focused into a narrow beam.
• Chromaticity Coordinates: The white light color point is defined on the CIE 1931 chromaticity diagram. The specification includes specific bin codes (K11, K21, K12, K22, K51, K61) with defined coordinate boundaries (x, y), ensuring color consistency across production batches. The tolerance for coordinate measurement is ±0.005.

2.2 Electrical Parameters

• Forward Voltage (V_F): The voltage drop across the LED when conducting 20mA. It is critically binned into codes from G1 (2.8V - 2.9V) to K1 (3.6V - 3.7V). This binning allows designers to select LEDs with consistent voltage characteristics, which is vital for current-limiting circuit design and power supply planning. The measurement tolerance is ±0.1V.
• Reverse Current (I_R): The leakage current when a reverse voltage of 5V is applied for 10ms. The maximum specified value is 10 μA, indicating good junction integrity and protection against minor reverse voltage events.
• Absolute Maximum Ratings: These are stress limits that must not be exceeded under any conditions to prevent permanent damage.
  • Maximum Continuous Forward Current (I_F): 30 mA.
  • Peak Pulse Forward Current (I_FP): 60 mA (under conditions of 0.1ms pulse width, 1/10 duty cycle).
  • Maximum Power Dissipation (P_d): 111 mW. Exceeding this can lead to overheating and accelerated degradation.
  • Electrostatic Discharge (ESD) Immunity: 1000V (Human Body Model), indicating a basic level of protection against static electricity.

2.3 Thermal Characteristics

Thermal management is crucial for LED longevity and performance stability.

• Thermal Resistance (R_THJ-S): The junction-to-solder point thermal resistance is specified as 450 °C/W. This value quantifies how effectively heat is transferred from the semiconductor junction to the PCB pad. A lower value is better. With this R_th, the junction temperature rise (ΔT_j) can be calculated as P_d * R_THJ-S. For example, at the maximum power of 111mW, the temperature rise would be approximately 50°C above the pad temperature.
• Temperature Limits:
  • Maximum Junction Temperature (T_j): 95 °C. The actual operating current must be derated based on the PCB's ability to dissipate heat to keep T_j below this limit.
  • Operating Temperature Range (T_opr): -40 °C to +85 °C.
  • Storage Temperature Range (T_stg): -40 °C to +85 °C.

3. Binning System Explanation

The LED is characterized and sorted (binned) based on key parameters to ensure uniformity in production batches, which is critical for applications requiring consistent visual or electrical performance.

3.1 Forward Voltage Binning

The forward voltage is sorted into ten distinct bins (G1, G2, H1, H2, I1, I2, J1, J2, K1). Each bin covers a 0.1V range from 2.8V to 3.7V. Designers can specify a voltage bin to match their driver circuit's output characteristics, improving efficiency and brightness consistency across multiple LEDs in an array.

3.2 Luminous Flux/Intensity Binning

Luminous intensity is binned into five codes (J20, K10, K20, L10, L20), with each representing a specific range of millicandela output. This allows for selection based on brightness requirements, enabling predictable light output levels in the final application.

3.3 Chromaticity (Color) Binning

The white point is defined on the CIE chromaticity diagram using six bin codes (K11, K21, K12, K22, K51, K61). Each bin is a quadrilateral defined by four sets of (x, y) coordinates. This precise binning ensures minimal visible color variation between LEDs from the same bin, which is especially important for applications using multiple LEDs side-by-side.

4. Performance Curve Analysis

While the PDF references typical optical characteristic curves, the provided data allows for analysis of key relationships.

4.1 Implied IV Relationship

The forward voltage bins and current ratings imply a standard diode IV curve. The voltage increases with current logarithmically. Operating above the recommended 20mA will cause a higher V_F and significantly increased power dissipation and junction temperature, which must be managed through heat sinking or current derating.

4.2 Temperature Characteristics

The specified parameters are at 25°C. In practice, LED performance changes with temperature. Typically, forward voltage decreases slightly with increasing temperature (negative temperature coefficient), while luminous output also decreases. The maximum junction temperature of 95°C is a critical design limit. The thermal resistance of 450°C/W means the PCB layout and copper area are vital for heat dissipation. For reliable long-term operation, the junction temperature should be kept as low as possible, well below the absolute maximum.

4.3 Spectral Distribution

As a phosphor-converted white LED, its spectrum consists of a peak from the blue chip (typically around 450-460nm) and a broader emission band from the yellow phosphor. The combined spectrum defines its Correlated Color Temperature (CCT) and color rendering properties, which are encapsulated within the specified chromaticity bins on the CIE diagram.

5. Mechanical and Package Information

5.1 Dimension Diagrams and Tolerances

The package is a rectangular surface-mount device. Key dimensions include a body size of 1.60mm x 0.80mm and a height of 0.98mm. The terminal (pad) dimensions and spacing are clearly defined in the recommended soldering pattern. All dimensional tolerances are ±0.2mm unless otherwise specified, which is standard for this component class.

5.2 Recommended Pad Design

The datasheet provides a suggested land pattern (soldering pattern) for PCB design. This pattern is crucial for achieving a reliable solder joint, proper alignment, and effective heat transfer from the LED to the PCB. Following this recommendation helps prevent tombstoning and ensures mechanical stability.

5.3 Polarity Identification

The LED is polarized. The cathode is typically marked, often by a green indicator or a notch on the package. Correct orientation during assembly is essential for the device to function. The datasheet diagram shows the anode and cathode positions relative to the package marking.

6. Soldering and Assembly Guidelines

6.1 Reflow Soldering Parameters

A dedicated section provides SMT reflow soldering instructions. While specific temperature profile details are not in the excerpt, general guidelines for moisture-sensitive Level 3 components apply. These typically involve:

• Pre-baking the components if the moisture barrier bag has been opened for longer than the specified floor life (usually 168 hours for MSL 3) to remove absorbed moisture.
• Using a standard lead-free (or leaded) reflow profile with a peak temperature not exceeding the component's maximum rating (linked to T_j and package integrity).
• Controlling the ramp-up and cooling rates to minimize thermal shock.

6.2 Handling and Storage Precautions

Key precautions include:

• ESD Protection: Handle using standard ESD-safe practices (wrist straps, conductive mats) as the ESD rating is 1000V HBM.
• Moisture Sensitivity: Adhere to MSL Level 3 protocols. Store in original, unopened moisture barrier bags with desiccant. Once opened, use within the specified time or rebake before soldering.
• Mechanical Stress: Avoid applying direct force to the LED lens or body during handling or placement.
• Cleaning: If cleaning is required post-soldering, use compatible solvents that do not damage the epoxy lens.

6.3 Storage Conditions

Components should be stored in their original packaging in an environment with a temperature between -40°C and +85°C and low humidity, as per the storage temperature rating.

7. Packaging and Ordering Information

7.1 Packaging Specifications

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

• Carrier Tape: The components are embedded in embossed carrier tape with specific pocket dimensions to hold the 1.6x0.8mm body securely.
• Reel: The tape is wound onto a reel. Standard reel dimensions (e.g., 7-inch or 13-inch) are specified to be compatible with SMT pick-and-place machines.
• Cardboard Box: The reels are packed in cardboard boxes for shipment and storage, providing physical protection.

7.2 Label Specifications and Moisture Barrier

The packaging includes labels containing product information, lot codes, and moisture sensitivity level (MSL 3) indicators. The components are packed in a moisture barrier bag with desiccant to maintain the specified humidity level during storage and transport, which is critical for MSL 3 parts.

7.3 Model Numbering and Bin Selection

The base model number is RF-WUD191DS-DD. When ordering, specific bin codes for forward voltage (e.g., G1, H2) and luminous intensity (e.g., L10, K20) must be specified to obtain the desired electrical and optical characteristics. Chromaticity bin codes may also be selectable.

8. Application Recommendations

8.1 Typical Application Scenarios

Beyond the listed uses (indicators, switch backlighting), this LED is suitable for:

• Consumer Electronics: Status LEDs on smart home devices, wearables, and USB peripherals.
• Automotive Interiors: Low-level illumination for controls and displays (subject to additional automotive qualification).
• Industrial HMIs: Panel indicators on machinery and test equipment where reliability is paramount.
• Medical Devices: Non-critical indicator lights on handheld instruments.

8.2 Critical Design Considerations

• Current Limiting: Always use a series current-limiting resistor or a constant-current driver. The value should be calculated based on the supply voltage and the forward voltage bin of the LED to ensure the current does not exceed the maximum continuous rating (30mA).
• Thermal Management: Due to the 450°C/W thermal resistance, PCB design is critical. Use adequate copper area (thermal pads) connected to the LED terminals to act as a heat sink. For arrays or high-ambient-temperature applications, perform a thorough thermal analysis to ensure T_j < 95°C.
• Optical Design: The 140-degree viewing angle is inherently diffuse. For applications requiring more directed light, external lenses or light guides may be necessary.
• Bin Consistency: For multi-LED applications, specify tight bins for voltage and chromaticity to ensure uniform brightness and color appearance.

9. Technical Comparison and Differentiation

Compared to generic non-binned LEDs or larger package LEDs, this device offers key differentiators:

• Size Advantage: The 1608 package (1.6x0.8mm) is significantly smaller than common 3528 or 5050 packages, enabling miniaturization.
• Performance Consistency: The comprehensive binning system for V_F, intensity, and color provides a level of predictability and uniformity that unbinned or loosely binned components lack, reducing design margin requirements.
• Wide-Angle Emission: The 140-degree viewing angle is wider than many competing SMD LEDs, which often range from 120 to 130 degrees, providing more even illumination without secondary optics.
• Balanced Specifications: It offers a good balance of brightness (up to 1200mcd), power handling (111mW), and thermal performance for its size category.

10. Frequently Asked Questions (Based on Technical Parameters)

Q1: Can I drive this LED directly from a 5V supply without a resistor?

A: No. Without a current-limiting resistor, the LED would draw excessive current, quickly exceeding its maximum power and current ratings, leading to immediate or rapid failure due to overheating.

Q2: What is the typical lifetime of this LED?

A: LED lifetime is typically defined as the point where luminous output degrades to 70% of its initial value (L70). While not explicitly stated here, lifetime is heavily dependent on operating conditions, primarily junction temperature. Operating well below the maximum T_j of 95°C (e.g., below 70-80°C) will ensure a very long operational life, often exceeding 50,000 hours.

Q3: How do I select the right current-limiting resistor value?

A: Use Ohm's Law: R = (V_supply - V_F) / I_F. Use the maximum V_F from your selected voltage bin for a conservative design to ensure current doesn't exceed your target (e.g., 20mA). For a 5V supply and a V_F bin of 3.2V max: R = (5 - 3.2) / 0.02 = 90 ohms. A standard 91-ohm or 100-ohm resistor would be suitable.

Q4: Why is the Moisture Sensitivity Level (MSL 3) important?

A> When moisture-sensitive components are subjected to high reflow soldering temperatures, the trapped moisture can vaporize rapidly, causing internal delamination or \"popcorning,\" which cracks the package. MSL 3 dictates that after the bag is opened, the components must be soldered within 168 hours (7 days) or be baked to remove moisture.

11. Practical Use Case Example

Scenario: Designing a Multi-Status Indicator Panel

A designer is creating a control panel with ten white LED indicators. Consistency in brightness and color is critical for user experience.

Implementation:

1. Bin Selection: Specify the same luminous intensity bin (e.g., L10 for high brightness) and the same chromaticity bin (e.g., K21) for all ten LEDs to ensure visual uniformity.
2. Circuit Design: Select a forward voltage bin (e.g., H1: 3.0-3.1V). Design a driver circuit with ten identical current-limiting resistor branches, each calculated using the maximum V_F from the H1 bin to guarantee consistent current and brightness across all LEDs even with minor V_F variations.
3. PCB Layout: For each LED, provide a copper pour around the solder pads as a thermal relief. Ensure the PCB has sufficient overall copper layers or thermal vias to dissipate the total heat from all ten LEDs.
4. Assembly: Follow MSL 3 handling procedures. Use the recommended reflow profile to ensure reliable solder joints without damaging the components.

This approach leverages the binning system to achieve a professional, consistent result.

12. Principle of Operation Introduction

The white light generation in this LED is based on the principle of phosphor conversion. The core is a semiconductor chip made of materials like indium gallium nitride (InGaN) that emits blue light when forward-biased (electroluminescence). This blue light is partially absorbed by a layer of yellow-emitting phosphor (typically YAG:Ce) deposited over the chip. The phosphor re-emits the absorbed energy as a broad spectrum of yellow light. The mixture of the remaining unabsorbed blue light and the converted yellow light results in the perception of white light by the human eye. The exact proportions of blue and yellow determine the Correlated Color Temperature (CCT), placing the white point within a specific region on the CIE chromaticity diagram, as defined by the bin codes.

13. Industry Trends and Context

The development of LEDs like this one is part of broader trends in optoelectronics:

• Miniaturization: Continuous drive towards smaller package sizes (e.g., from 3528 to 2016 to 1608) to enable thinner and more compact end products.
• Increased Efficiency: Ongoing improvements in chip technology and phosphor efficiency lead to higher luminous efficacy (more light output per watt of electrical input), though this spec sheet focuses on intensity at a fixed current.
• Enhanced Color Consistency: Tighter binning and improved manufacturing processes ensure better color uniformity, which is increasingly demanded in professional lighting and display applications.
• Reliability and Standardization: Components are designed to meet strict international standards for soldering (IPC), moisture sensitivity (JEDEC MSL), and environmental compliance (RoHS, REACH), as reflected in this datasheet.

This component represents a mature, well-characterized solution within these evolving market demands, offering a reliable balance of size, performance, and cost for volume production.