SMD LED LTW-110ZDS5 Datasheet - White Light - 20mA - 70mW - English Technical Document

1. Product Overview

The LTW-110ZDS5 is a surface-mount device (SMD) light-emitting diode (LED) designed for modern, space-constrained electronic assemblies. It belongs to a family of miniature components optimized for automated pick-and-place and reflow soldering processes. This specific model utilizes an InGaN (Indium Gallium Nitride) semiconductor chip to produce white light, housed in a side-viewing package configuration. This orientation is particularly advantageous for applications where light needs to be emitted parallel to the printed circuit board (PCB) surface, such as in edge-lit panels or status indicators viewable from the side of a device.

The core design philosophy behind this component is to provide a reliable, bright light source that integrates seamlessly into high-volume manufacturing workflows. Its package conforms to EIA (Electronic Industries Alliance) standards, ensuring compatibility with industry-standard handling and placement equipment. The component is supplied on 8mm carrier tape wound onto 7-inch diameter reels, which is the standard format for automated assembly lines, facilitating efficient loading into placement machines.

1.1 Features and Core Advantages

• Environmental Compliance: The device is manufactured to meet ROHS (Restriction of Hazardous Substances) directives, ensuring it is free from specific hazardous materials like lead, mercury, and cadmium.
• Advanced Semiconductor Technology: Employs an Ultra Bright InGaN chip. InGaN technology is known for its high efficiency and ability to produce bright blue and white light, which is then typically converted to white using a phosphor coating.
• Manufacturing Readiness: Features a tin-plated termination, which enhances solderability, especially with lead-free (Pb-free) solder alloys. It is fully compatible with infrared (IR) reflow soldering processes, the dominant method for SMD assembly.
• Design Compatibility: The device is I.C. (Integrated Circuit) compatible, meaning its driving requirements (current, voltage) can be easily managed by standard logic-level outputs or simple driver circuits commonly found alongside other ICs on a board.
• Automation Friendly: The standardized EIA package and tape-and-reel packaging ensure reliable performance in high-speed automatic placement equipment, minimizing placement errors and increasing production throughput.

1.2 Target Market and Applications

This LED is engineered for a broad spectrum of electronic equipment where reliable indication, backlighting, or symbolic illumination is required in a compact form factor. Its primary application domains include:

• Telecommunication Equipment: Status indicators on routers, modems, switches, and base stations.
• Office Automation and Computing: Keyboard backlighting in laptops, status lights on printers, scanners, and external storage devices.
• Consumer Electronics and Home Appliances: Power, mode, or function indicators on audio/video equipment, kitchen appliances, and smart home devices.
• Industrial Equipment: Panel indicators for machinery, control systems, and instrumentation.
• Specialized Displays: Backlighting for keypads, micro-displays, and providing illumination for symbols or icons on control panels.

2. Technical Parameters: In-Depth Objective Interpretation

The performance of the LTW-110ZDS5 is defined by a comprehensive set of electrical, optical, and thermal parameters. Understanding these specifications is crucial for proper circuit design and ensuring long-term reliability.

2.1 Absolute Maximum Ratings

These ratings define the stress limits beyond which permanent damage to the device may occur. Operation under or at these limits is not guaranteed and should be avoided in normal use.

• Power Dissipation (Pd): 70 mW. This is the maximum amount of electrical power the device can dissipate as heat without degrading. Exceeding this can lead to excessive junction temperature, reduced light output, and shortened lifespan.
• Forward Current (DC): 20 mA. This is the maximum continuous direct current recommended for reliable operation. The typical operating condition specified in the datasheet is 5mA.
• Peak Forward Current: 100 mA, but only under pulsed conditions (1/10 duty cycle, 0.1ms pulse width). This allows for brief moments of higher brightness, such as in blinking indicators, without overheating.
• Operating Temperature Range: -20°C to +80°C. The device is guaranteed to function within this ambient temperature range.
• Storage Temperature Range: -40°C to +85°C. The device can be stored without operation within this wider range.
• Infrared Soldering Condition: Withstands 260°C peak temperature for 10 seconds. This is a critical parameter for Pb-free assembly processes, defining the thermal profile the component can endure during reflow soldering.

2.2 Electrical and Optical Characteristics (at Ta=25°C)

These are the typical performance parameters measured under standard test conditions.

• Luminous Intensity (Iv): Ranges from 28.0 mcd (millicandela) Minimum to 112.0 mcd Maximum at a test current (IF) of 5mA. The actual value for a specific unit falls into a bin rank (N, P, Q). Intensity is measured with a filter simulating the human eye's photopic response (CIE curve).
• Viewing Angle (2θ1/2): 130 degrees. This is the full angle at which the luminous intensity drops to half of its peak value (measured at 0 degrees, directly perpendicular to the chip). A wide viewing angle like this is characteristic of side-view LEDs and provides broad, even illumination.
• Chromaticity Coordinates (x, y): Typical values are x=0.304, y=0.301 at 5mA. These coordinates on the CIE 1931 chromaticity diagram define the perceived color of the white light. Specific units are classified into hue bins (S1-S6). A tolerance of ±0.01 is applied to these coordinates.
• Forward Voltage (VF): Between 2.70V and 3.15V at 5mA. This is the voltage drop across the LED when conducting the specified current. Units are binned into groups (L7, L8, L9) based on this parameter. A lower VF generally indicates higher electrical efficiency.
• Reverse Current (IR): 0.6 to 1.2 μA at a reverse voltage (VR) of 10mA. Critical Note: The datasheet explicitly states this test condition is for IR (Infrared) testing only and that the device is not designed for reverse operation. Applying a reverse bias in circuit could damage the LED.

2.3 Thermal Characteristics

While not explicitly given as a thermal resistance (RθJA) figure, the thermal performance is implied through the power dissipation rating (70mW) and the operating temperature range. The maximum junction temperature is a key factor in LED longevity. Operating the LED at currents below the maximum, ensuring adequate PCB copper area for heat sinking (as shown in the recommended pad layout), and maintaining ambient temperature within spec are all essential for managing thermal performance.

3. Bin Ranking System Explanation

To account for natural variations in semiconductor manufacturing, LEDs are sorted into performance bins. This allows designers to select components with tightly controlled characteristics for their application.

3.1 Forward Voltage (VF) Rank

LEDs are sorted based on their forward voltage drop at 5mA.
- Bin L7: VF = 2.70V to 2.85V
- Bin L8: VF = 2.85V to 3.00V
- Bin L9: VF = 3.00V to 3.15V
Tolerance on each bin is ±0.1V. Selecting LEDs from the same VF bin ensures consistent brightness when driven by a constant voltage source or simplifies current-limiting resistor calculation for series strings.

3.2 Luminous Intensity (Iv) Rank

LEDs are sorted based on their light output intensity at 5mA.
- Bin N: Iv = 28.0 mcd to 45.0 mcd
- Bin P: Iv = 45.0 mcd to 71.0 mcd
- Bin Q: Iv = 71.0 mcd to 112.0 mcd
Tolerance on each bin is ±15%. This binning is crucial for applications requiring uniform brightness across multiple LEDs, such as in backlighting arrays or multi-indicator panels.

3.3 Hue (Chromaticity) Rank

This is the most complex binning, defining the color point of the white light on the CIE 1931 diagram. Six bins (S1 through S6) are defined, each representing a small quadrilateral area on the (x,y) coordinate plane. For example, Bin S3 covers coordinates approximately from (0.294, 0.254) to (0.314, 0.315). A tolerance of ±0.01 is applied. This binning is essential for applications where color consistency is critical, preventing noticeable differences in white tint (e.g., cool white vs. warm white) between adjacent LEDs.

4. Performance Curve Analysis

The datasheet includes typical characteristic curves which provide valuable insights beyond the tabulated data points.

4.1 Relative Luminous Intensity vs. Forward Current

This curve shows how light output increases with drive current. It is typically non-linear. While output rises with current, efficiency (lumens per watt) often peaks at a current lower than the absolute maximum. Operating at the typical 5mA condition likely represents a good balance of brightness and efficiency for this device.

4.2 Forward Voltage vs. Forward Current

This curve illustrates the diode's I-V characteristic. The forward voltage increases with current but not linearly. Understanding this curve is important for designing driver circuits, especially when using constant-voltage supplies, as a small change in voltage can lead to a large change in current and, consequently, brightness.

4.3 Relative Luminous Intensity vs. Ambient Temperature

This curve is critical for understanding thermal effects. As the ambient temperature rises, the luminous intensity of an LED generally decreases. The slope of this curve indicates the thermal sensitivity of the device. Designers must derate the expected light output if the LED will operate in a high-temperature environment.

5. Mechanical and Package Information

5.1 Package Dimensions

The datasheet provides a detailed mechanical drawing of the LED. Key dimensions include the overall length, width, and height, the size and position of the semiconductor chip cavity, and the location and size of the solderable terminals. All dimensions are in millimeters with a standard tolerance of ±0.1mm unless otherwise noted. The side-view design means the primary light-emitting surface is on the longer side of the package.

5.2 Recommended PCB Attachment Pad and Polarity

A land pattern (footprint) recommendation is provided for PCB design. This shows the optimal size and shape of the copper pads to ensure good solder joint formation during reflow. The diagram clearly indicates the anode and cathode connections, which is essential for correct orientation during placement and to ensure the LED lights up when power is applied. The cathode is typically identified by a marker on the LED package itself, such as a notch, dot, or green marking.

6. Soldering and Assembly Guidelines

6.1 IR Reflow Soldering Profile (Pb-Free Process)

A suggested reflow profile is provided for lead-free soldering:
- Pre-heat: 150-200°C.
- Pre-heat Time: Maximum 120 seconds.
- Peak Temperature: Maximum 260°C.
- Time Above Liquidus (at peak): Maximum 10 seconds, and this reflow process should not be performed more than two times.
The datasheet correctly notes that the optimal profile depends on the specific PCB assembly (board thickness, number of components, solder paste). The profile should be characterized for the specific production line but should remain within these component-level limits.

6.2 Hand Soldering (If Required)

For repair or prototyping:
- Soldering Iron Temperature: Maximum 300°C.
- Soldering Time: Maximum 3 seconds per joint.
- This should be performed only once to minimize thermal stress.

6.3 Cleaning

If cleaning after soldering is necessary, only specified solvents should be used to avoid damaging the plastic package. The datasheet recommends immersion in ethyl alcohol or isopropyl alcohol at normal temperature for less than one minute. Unspecified chemical liquids must be avoided.

7. Storage and Handling Precautions

7.1 Electrostatic Discharge (ESD) Sensitivity

The LED can be damaged by static electricity and electrical surges. It is recommended to use a wrist strap or anti-static gloves when handling. All equipment, including workstations and soldering irons, must be properly grounded.

7.2 Moisture Sensitivity and Storage

The component has a Moisture Sensitivity Level (MSL) of 3.
- Sealed Package: Can be stored at ≤30°C and ≤90% RH. The shelf life in the original moisture-proof bag with desiccant is one year.
- Opened Package: The ambient should not exceed 30°C / 60% RH. Components removed from the original packaging should be reflow-soldered within one week.
- Extended Storage (Out of Bag): Must be stored in a sealed container with desiccant or in a nitrogen desiccator.
- Rebaking: If exposed for more than one week, components must be baked at approximately 60°C for at least 20 hours before soldering to remove absorbed moisture and prevent \"popcorning\" during reflow.

8. Packaging and Ordering Information

8.1 Tape and Reel Specifications

The device is supplied on 8mm wide embossed carrier tape. Key tape dimensions include pocket spacing (pitch), pocket size, and cover tape seal positions. The tape is wound onto standard 7-inch (178mm) diameter reels.

8.2 Reel Packaging Details

• Quantity per Reel: 3000 pieces.
• Minimum Packing Quantity: 500 pieces for remainder quantities.
• Cover Tape: Empty pockets are sealed with top cover tape.
• Missing Components: A maximum of two consecutive missing lamps is allowed on the reel, as per standard practice.
• Standard Compliance: Packaging follows ANSI/EIA-481 specifications.

9. Application Notes and Design Considerations

9.1 Typical Application Circuits

The LED requires a current-limiting mechanism. The simplest method is a series resistor. The value is calculated using Ohm's Law: R = (Vsupply - VF_LED) / IF. For example, with a 5V supply, a VF of 3.0V (typical), and a desired IF of 5mA: R = (5V - 3.0V) / 0.005A = 400 Ohms. A 390 Ohm or 430 Ohm standard resistor would be suitable. For applications requiring constant brightness over varying supply voltage or temperature, a constant-current driver circuit is recommended.

9.2 Design for Reliability and Longevity

• Current Derating: Operating the LED at or below the typical 5mA current, rather than the absolute maximum 20mA, will significantly extend its operational life and improve long-term luminous maintenance.
• Thermal Management: Use the recommended PCB pad layout, which includes thermal relief connections. For high-power or high-ambient-temperature applications, consider adding additional copper area or thermal vias under the LED's footprint to conduct heat away from the junction.
• Reverse Voltage Protection: As the device is not designed for reverse bias, ensure the circuit design prevents this condition. In AC or bipolar circuits, a parallel protection diode may be necessary.

10. Technical Comparison and Differentiation

Compared to older LED technologies like GaP (Gallium Phosphide) or standard GaN devices, the InGaN chip in the LTW-110ZDS5 offers superior luminous efficacy, meaning more light output per unit of electrical power consumed. The side-view package differentiates it from top-view LEDs, solving specific optical design challenges where lateral light emission is required. Its compatibility with high-temperature Pb-free reflow profiles makes it a modern component suitable for current environmental regulations and manufacturing standards, unlike older components that may only be suitable for leaded solder or wave soldering.

11. Frequently Asked Questions (Based on Technical Parameters)

Q: Can I drive this LED directly from a 3.3V microcontroller pin?
A: Possibly, but with caution. The typical VF is 3.0V, leaving only 0.3V for the current-limiting resistor. At 5mA, this requires a 60 Ohm resistor. The low voltage headroom means brightness may be inconsistent due to small variations in VF or supply voltage. A dedicated LED driver or a higher supply voltage is more reliable.

Q: What does the \"ZDS5\" in the part number signify?
A: While the full naming convention isn't detailed here, in many manufacturer systems, such suffixes indicate specific attributes like color (White), package style (Side-view), binning (intensity/color rank), and termination plating. Refer to the manufacturer's product guide for the exact breakdown.

Q: How do I ensure color consistency in my multi-LED design?
A: Order components from the same Hue (S1-S6) bin and the same Luminous Intensity (N, P, Q) bin. Work with your distributor to specify these bin codes for your order to guarantee matched performance.

Q: Is this LED suitable for automotive interior lighting?
A: The operating temperature range (-20°C to +80°C) may cover some interior applications, but automotive grades typically require a wider range (e.g., -40°C to +105°C or 125°C) and more rigorous reliability qualifications (AEC-Q102). This datasheet does not claim such compliance, so it is intended for \"ordinary electronic equipment\" as defined in the cautions section.

12. Practical Use Case Example

Scenario: Designing a status indicator panel for a network switch.
The panel has 10 identical status LEDs for link/activity. Requirements: uniform white color, consistent brightness, and reliable operation 24/7.
Design Steps:
1. Circuit Design: Use a stable 5V rail. Calculate a series resistor for ~5mA drive current per LED. Assuming VF bin L8 (2.85-3.00V), use the max VF for worst-case brightness calculation: R = (5V - 3.0V) / 0.005A = 400 Ohms. 2. Component Selection: Specify to the supplier: Part No. LTW-110ZDS5, with all 10 pieces from the same Hue Bin (e.g., S3) and the same Luminous Intensity Bin (e.g., P). This ensures visual consistency. 3. PCB Layout: Implement the recommended solder pad footprint from the datasheet. Connect the cathode pads to a common ground plane for good heat dissipation. 4. Assembly: Follow the Pb-free reflow profile guidelines, ensuring peak temperature does not exceed 260°C. 5. Result: A professional-looking panel with ten identical, bright white indicators that will maintain their performance over the long term due to conservative current drive and proper thermal design.

13. Operational Principle Introduction

An LED is a semiconductor diode. When a forward voltage exceeding its bandgap is applied, electrons from the n-type semiconductor recombine with holes from the p-type semiconductor in the active region (the InGaN chip). This recombination releases energy in the form of photons (light). The specific wavelength (color) of the light is determined by the bandgap energy of the semiconductor material. InGaN has a bandgap that produces light in the blue/ultraviolet spectrum. To create white light, the LED chip is coated with a phosphor material. The blue/UV light from the chip excites the phosphor, which then re-emits light across a broader spectrum, combining to produce the perception of white light. The side-view package incorporates a molded plastic lens that shapes the light output, creating the wide 130-degree viewing angle.

14. Technology Trends and Context

The LTW-110ZDS5 represents a mature and widely adopted technology. Current trends in SMD LEDs focus on several key areas: Increased Efficiency: Ongoing development of chip designs and phosphors to achieve higher lumens per watt (lm/W), reducing energy consumption for the same light output. Improved Color Quality: Enhancing the Color Rendering Index (CRI) of white LEDs, making them suitable for applications where accurate color perception is vital, such as retail lighting or photography. Miniaturization: Development of even smaller package sizes (e.g., 0402, 0201 metric) for ultra-compact devices like wearables and miniaturized sensors. Integrated Solutions: Growth of LEDs with built-in drivers, controllers, or multiple color chips (RGB) in a single package, simplifying circuit design for smart lighting and dynamic color effects. While this component is a workhorse for standard indicator and backlight functions, these trends drive innovation in more specialized market segments.