LTW-C193DS5 SMD LED Datasheet - 0.35mm Thin - 3.15V Max - 70mW - White - English Technical Document

1. Product Overview

This document details the specifications for an ultra-thin, surface-mount device (SMD) light-emitting diode (LED). The component is designed for applications requiring a compact form factor and high-brightness white light output. Its primary construction utilizes InGaN (Indium Gallium Nitride) semiconductor technology, which is known for efficient white light generation. The package is exceptionally thin, making it suitable for space-constrained designs in modern electronics.

The core advantages of this LED include its compliance with environmental regulations, compatibility with automated assembly processes, and suitability for standard infrared reflow soldering techniques. This makes it an ideal choice for high-volume manufacturing. The target market encompasses a wide range of consumer and industrial electronics where indicator lights, backlighting, or general illumination is required in a minimal footprint.

2. In-Depth Technical Parameter Analysis

2.1 Absolute Maximum Ratings

These ratings define the limits beyond which permanent damage to the device may occur. Operation under these conditions is not guaranteed.

• Power Dissipation (Pd): 70 mW. This is the maximum amount of power the LED can dissipate as heat without degrading performance or causing failure. Exceeding this limit risks thermal runaway.
• Peak Forward Current (I_FP): 100 mA. This is the maximum instantaneous current allowed under pulsed conditions (1/10 duty cycle, 0.1ms pulse width). It is significantly higher than the continuous current rating.
• DC Forward Current (I_F): 20 mA. This is the maximum recommended continuous forward current for reliable long-term operation. Designers should typically operate below this value.
• Operating Temperature Range (T_opr): -20°C to +80°C. The device is guaranteed to function within this ambient temperature range.
• Storage Temperature Range (T_stg): -55°C to +105°C. The device can be stored without applied power within this wider temperature range.
• Infrared Soldering Condition: 260°C for 10 seconds. This defines the peak temperature and time profile the package can withstand during reflow soldering.

2.2 Electro-Optical Characteristics

These parameters are measured at a standard ambient temperature of 25°C and define the device's performance under normal operating conditions.

• Luminous Intensity (I_V): Ranges from 45.0 mcd (minimum) to 180.0 mcd (typical) at a test current (I_F) of 5 mA. This measures the perceived brightness of the light output as seen by the human eye, using a filter that approximates the CIE photopic response curve.
• Viewing Angle (2θ_1/2): 130 degrees (typical). This is the full angle at which the luminous intensity drops to half of its maximum value (on-axis). A wide viewing angle like this indicates a more diffuse, lambertian-like emission pattern suitable for area illumination.
• Chromaticity Coordinates (x, y): Typical values are x=0.294, y=0.286 at I_F = 5mA. These coordinates plot the color of the white light on the CIE 1931 chromaticity diagram, defining its specific hue or "whiteness." A tolerance of ±0.01 applies to these coordinates.
• Forward Voltage (V_F): Ranges from 2.70 V (minimum) to 3.15 V (maximum) at I_F = 5mA. This is the voltage drop across the LED when conducting current. It is a critical parameter for driving circuit design (e.g., current-limiting resistor calculation).
• Reverse Current (I_R): 10 μA (maximum) at a Reverse Voltage (V_R) of 5V. This parameter is for test purposes only; the device is not designed for operation under reverse bias. Applying reverse voltage in-circuit can cause immediate failure.

Important Notes: The datasheet emphasizes Electrostatic Discharge (ESD) sensitivity. Proper handling with wrist straps and grounded equipment is mandatory. The specified tester for chromaticity and luminous intensity is a CAS140B instrument.

3. Binning System Explanation

To ensure consistency in mass production, LEDs are sorted into performance bins. This allows designers to select components with tightly controlled characteristics.

3.1 Forward Voltage (V_F) Binning

LEDs are categorized into three bins based on their forward voltage at 5mA:
- Bin A: 2.70V - 2.85V
- Bin B: 2.85V - 3.00V
- Bin C: 3.00V - 3.15V
Tolerance on each bin is ±0.1V. Selecting a specific bin ensures uniform brightness and current draw in parallel arrays.

3.2 Luminous Intensity (I_V) Binning

LEDs are sorted into three brightness bins at 5mA:
- Bin P: 45.0 mcd - 71.0 mcd
- Bin Q: 71.0 mcd - 112.0 mcd
- Bin R: 112.0 mcd - 180.0 mcd
Tolerance on each bin is ±15%. This allows for selection based on required brightness levels.

3.3 Hue (Color) Binning

The white color point is precisely controlled using six bins (S1 through S6) defined by quadrilaterals on the CIE 1931 chromaticity diagram. Each bin specifies a small region of allowed x and y coordinate pairs. The typical value (x=0.294, y=0.286) falls within the S1 and S3 regions. A tolerance of ±0.01 applies to the coordinates. This binning is crucial for applications requiring consistent white color across multiple LEDs, such as display backlighting.

4. Performance Curve Analysis

While specific graphical curves are referenced in the datasheet (e.g., Fig.6 for viewing angle), the provided data allows for conceptual analysis of key relationships.

• Current vs. Luminous Intensity (I-I_V Curve): The luminous intensity is directly proportional to the forward current, typically following a near-linear relationship at lower currents before saturating at higher currents. Operating at the recommended 5mA test point ensures linear and predictable brightness control.
• Current vs. Forward Voltage (I-V Curve): An LED's I-V characteristic is exponential. The specified V_F range at 5mA is critical. A small increase in voltage can lead to a large increase in current, which is why constant-current drivers are preferred over constant-voltage sources.
• Temperature Dependence: The luminous intensity of InGaN LEDs typically decreases with increasing junction temperature (thermal quenching). The operating temperature range of -20°C to +80°C must be considered, as output and color may shift at temperature extremes. Proper PCB thermal management is essential for maintaining performance.

5. Mechanical and Package Information

5.1 Package Dimensions

The LED features an industry-standard EIA package outline. The key feature is its super-thin profile of 0.35 mm. All dimensions are provided in millimeters with a standard tolerance of ±0.10 mm unless otherwise specified. Detailed dimensioned drawings are included in the datasheet for PCB footprint design.

5.2 Soldering Pad Layout

Recommended solder pad dimensions are provided to ensure reliable solder joint formation and proper alignment during reflow. A note suggests a maximum stencil thickness of 0.10mm for solder paste application, which is critical for controlling solder volume on such a small component.

5.3 Polarity Identification

The datasheet includes markings or diagrams to identify the anode and cathode terminals. Correct polarity is essential for device operation. Applying reverse polarity can instantly destroy the LED.

6. Soldering and Assembly Guidelines

6.1 Reflow Soldering Parameters

A detailed infrared (IR) reflow soldering profile is recommended, based on JEDEC standards:
- Pre-heat: 150–200°C
- Pre-heat Time: 120 seconds maximum
- Peak Temperature: 260°C maximum
- Time Above Liquidus: 10 seconds maximum (recommended for a maximum of two reflow cycles)
These parameters are designed to properly melt the solder paste without subjecting the LED package to excessive thermal stress.

6.2 Hand Soldering

If hand soldering is necessary, extreme care is required:
- Iron Temperature: 300°C maximum
- Contact Time: 3 seconds maximum per pad
- Limit: One soldering cycle only
Prolonged heat from a soldering iron can easily damage the semiconductor die or the plastic package.

6.3 Storage and Handling Conditions

• Sealed Package: Store at ≤30°C and ≤90% RH. Use within one year of opening the moisture barrier bag.
• Opened Package: For components removed from their dry-pack, the ambient should not exceed 30°C / 60% RH. It is recommended to complete IR reflow within 672 hours (28 days).
• Extended Storage: Components exposed beyond 672 hours should be baked at approximately 60°C for at least 20 hours before soldering to remove absorbed moisture and prevent "popcorning" during reflow.

6.4 Cleaning

Only specified cleaning agents should be used. Recommended solvents are ethyl alcohol or isopropyl alcohol at room temperature. The LED should be immersed for less than one minute. Unspecified chemicals may damage the package material or optical lens.

7. Packaging and Ordering Information

7.1 Tape and Reel Specifications

The LEDs are supplied in industry-standard 8mm carrier tape wound onto 7-inch (178mm) diameter reels. This packaging is compatible with automated pick-and-place machines.

• Reel Quantity: 5000 pieces per full reel.
• Minimum Order Quantity (MOQ): 500 pieces for remainder quantities.
• Quality: The tape has a top cover, and the maximum number of consecutive missing components (empty pockets) is two, in accordance with ANSI/EIA 481-1-A-1994 standards.

7.2 Part Number Interpretation

The part number LTW-C193DS5 contains coded information:
- LTW: Likely denotes the product series (Lite-On White).
- C193: Specific device identifier within the series.
- DS5: May indicate package type, bin code, or other variant information. The exact breakdown should be confirmed with the manufacturer's full part numbering guide.

8. Application Recommendations

8.1 Typical Application Scenarios

• Status Indicators: Power, connectivity, or activity lights in consumer electronics (routers, TVs, appliances).
• Backlighting: Edge-lighting for small LCD displays, keypad illumination.
• Decorative Lighting: Accent lighting in thin-profile devices.
• General Signage: Low-level illumination where space is at a premium.

8.2 Critical Design Considerations

• Current Limiting: Always use a series resistor or constant-current driver. Calculate the resistor value using R = (V_supply - V_F) / I_F. Use the maximum V_F from the datasheet (3.15V) to ensure current does not exceed limits even with a low-V_F device.
• Thermal Management: Although power dissipation is low (70mW), ensure the PCB provides adequate thermal relief, especially if multiple LEDs are used or if ambient temperatures are high. Copper pads and thermal vias can help.
• ESD Protection: Incorporate ESD protection diodes on signal lines connected to the LED, or ensure the driving circuit has inherent protection. Follow strict ESD protocols during handling and assembly.
• Optical Design: Consider the 130-degree viewing angle. For focused light, a secondary optic (lens) may be required. The yellow lens of the package helps diffuse the light and achieve the specified color coordinates.

9. Technical Comparison and Differentiation

Compared to standard SMD LEDs (e.g., 0603, 0805 packages), this device's primary differentiator is its 0.35mm thickness. This is significantly thinner than conventional packages, enabling design in ultra-slim products. The use of InGaN technology for white light offers advantages in efficiency and color stability over older technologies like phosphor-converted blue LEDs with different structures. Its compatibility with standard IR reflow processes and automated tape-and-reel packaging aligns it with modern, high-volume SMT assembly lines, reducing manufacturing complexity compared to through-hole or manually placed components.

10. Frequently Asked Questions (Based on Technical Parameters)

1. Q: Can I drive this LED directly from a 5V supply?
   A: No. With a typical V_F of ~3V, connecting it directly to 5V would cause excessive current and immediate failure. You must use a current-limiting resistor. For example, targeting I_F=5mA: R = (5V - 3.15V) / 0.005A = 370Ω. Use the next standard value, e.g., 390Ω.
2. Q: What is the difference between Peak Forward Current and DC Forward Current?
   A: DC Forward Current (20mA) is for continuous operation. Peak Forward Current (100mA) is a short-duration, pulsed rating used for multiplexing or testing. Operating continuously at 100mA will destroy the LED.
3. Q: Why is the storage condition for opened packages so strict (672 hours)?
   A> SMD packages can absorb moisture from the air. During the high heat of reflow soldering, this moisture can vaporize rapidly, causing internal delamination or cracking ("popcorning"). The 672-hour limit and baking procedure mitigate this risk.
4. Q: How do I interpret the Hue Bin codes (S1-S6)?
   A: These codes define a small area on the CIE color chart. For consistent color across a panel, specify and use LEDs from the same Hue bin. Mixing bins may result in visibly different shades of white.

11. Practical Design and Usage Case

Scenario: Designing a status indicator panel for a wearable device.
The device requires four white LEDs to indicate battery level. Space is extremely limited, with a maximum component height of 0.5mm.
Solution: The 0.35mm thick LTW-C193DS5 is selected. To ensure uniform brightness, all four LEDs are specified from the same Luminous Intensity bin (e.g., Bin Q). To guarantee identical white color, they are also specified from the same Hue bin (e.g., S3). The driving circuit uses a microcontroller GPIO pin with a 390Ω series resistor per LED (calculated for a 3.3V supply). The PCB layout includes thermal relief pads connected to a small ground plane for heat dissipation. The LEDs are placed after all other reflow steps to minimize thermal exposure, adhering to the 672-hour rule after the bag is opened.

12. Technology Principle Introduction

This LED generates white light using an InGaN (Indium Gallium Nitride) semiconductor chip. InGaN materials are capable of emitting light in the blue to ultraviolet spectrum. To produce white light, the primary method involves combining a blue-emitting InGaN chip with a yellow phosphor coating (cerium-doped yttrium aluminum garnet, or YAG:Ce). The blue light from the chip excites the phosphor, which then emits yellow light. The combination of the remaining blue light and the generated yellow light is perceived by the human eye as white. This is known as a phosphor-converted white LED. The specific mix of phosphor determines the correlated color temperature (CCT) and chromaticity coordinates (x, y) on the CIE diagram.

13. Industry Trends and Developments

The trend in indicator and miniature lighting LEDs continues toward increased efficiency (more lumens per watt), smaller form factors (reduced footprint and thickness), and improved color rendering (higher CRI - Color Rendering Index, though not specified for this indicator-type LED). There is also a strong drive for higher reliability and longer lifetime under various environmental conditions. Manufacturing processes are being refined to achieve tighter binning tolerances, providing more consistent performance for demanding applications like display backlighting. The push for miniaturization, as exemplified by this 0.35mm component, is driven by the consumer electronics industry's demand for thinner and more compact devices.