Dual Color SMD LED LTW-C195DSKF-5A Datasheet - White & Orange - 20-30mA - 72-75mW - English Technical Document

1. Product Overview

The LTW-C195DSKF-5A is a dual-color, surface-mount device (SMD) LED designed for modern electronic applications requiring compact, reliable, and bright indicator or backlighting solutions. It integrates two distinct semiconductor chips within a single EIA-standard package: an InGaN (Indium Gallium Nitride) chip for white light emission and an AlInGaP (Aluminum Indium Gallium Phosphide) chip for orange light emission. This configuration allows for bi-color operation from a single component footprint, saving valuable PCB space. The device is packaged on 8mm tape supplied on 7-inch diameter reels, making it fully compatible with high-speed automated pick-and-place assembly equipment. It is classified as a Green Product and complies with RoHS (Restriction of Hazardous Substances) directives.

2. Technical Parameter Deep-Dive

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 for reliable long-term performance.

• Power Dissipation (Pd): White Chip: 72 mW, Orange Chip: 75 mW. This is the maximum allowable power loss as heat. Exceeding this can lead to excessive junction temperature and accelerated degradation.
• Peak Forward Current (I_FP): White: 100 mA, Orange: 80 mA. This is the maximum instantaneous current, typically specified under pulsed conditions (1/10 duty cycle, 0.1ms pulse width) to prevent thermal overload during short transients.
• DC Forward Current (I_F): White: 20 mA, Orange: 30 mA. This is the maximum continuous forward current recommended for normal operation. The orange chip can handle a higher continuous current.
• Reverse Voltage (V_R): 5 V for both chips. Applying a reverse voltage higher than this can cause breakdown and damage. The datasheet explicitly notes that reverse voltage operation cannot be continuous.
• Temperature Ranges: Operating: -20°C to +80°C; Storage: -30°C to +100°C. These define the environmental limits for functional use and non-operational storage.
• Infrared Reflow Soldering: Withstands 260°C peak temperature for 10 seconds, which aligns with common lead-free (Pb-free) solder reflow profiles.

2.2 Electrical & Optical Characteristics

These are the typical and guaranteed performance parameters measured at a standard test condition of Ta=25°C and I_F=5mA, unless otherwise specified.

• Luminous Intensity (I_V): A key measure of brightness.
  • White: Minimum 45.0 mcd, Typical value not stated, Maximum 180.0 mcd.
  • Orange: Minimum 11.2 mcd, Typical value not stated, Maximum 71.0 mcd.
  • Measurement follows the CIE eye-response curve using specified test equipment (e.g., CAS140B).
• Viewing Angle (2θ_1/2): 130 degrees (typical) for both colors. This wide viewing angle is characteristic of the package lens design, providing a broad emission pattern suitable for indicator applications.
• Wavelength Parameters (Orange Chip):
  • Peak Emission Wavelength (λ_P): 611 nm (typical). The wavelength at which the spectral power output is highest.
  • Dominant Wavelength (λ_d): 605 nm (typical). The single wavelength perceived by the human eye that matches the LED's color.
  • Spectral Line Half-Width (Δλ): 20 nm (typical). The bandwidth of the emitted spectrum at half the peak intensity, indicating color purity.
• Chromaticity Coordinates (Orange Chip): x=0.3, y=0.3 (typical). These CIE 1931 coordinates define the precise orange color point on the chromaticity diagram. A tolerance of ±0.01 is applied to these coordinates.
• Forward Voltage (V_F):
  • White: Typical 2.75V, Maximum 3.15V at I_F=5mA.
  • Orange: Typical 2.00V, Maximum 2.40V at I_F=5mA.
  • The lower V_F of the orange chip is consistent with the AlInGaP material system.
• Reverse Current (I_R): Maximum 10 µA (White) and 100 µA (Orange) at V_R=5V. This is the small leakage current when the device is reverse-biased.

Electrostatic Discharge (ESD) Caution: LEDs are sensitive to static electricity. Handling procedures must include the use of wrist straps, anti-static gloves, and properly grounded equipment and workstations to prevent damage from ESD or surge events.

3. Binning System Explanation

To manage natural variations in semiconductor manufacturing, LEDs are sorted into performance bins. The LTW-C195DSKF-5A uses separate binning for luminous intensity and forward voltage.

3.1 Luminous Intensity (I_V) Binning

• White Chip: Bins P (45.0-71.0 mcd), Q (71.0-112.0 mcd), R (112.0-180.0 mcd). Tolerance within each bin is ±15%.
• Orange Chip: Bins L (11.2-18.0 mcd), M (18.0-28.0 mcd), N (28.0-45.0 mcd), P (45.0-71.0 mcd). Tolerance within each bin is ±15%.
• The specific bin code is marked on the packaging, allowing designers to select LEDs with consistent brightness for their application.

3.2 Forward Voltage (V_F) Binning (White Chip Only)

• Bins A (2.55-2.75V), B (2.75-2.95V), C (2.95-3.15V). Tolerance within each bin is ±0.1V.
• Binning V_F helps in designing more consistent current drive circuits, especially when multiple LEDs are connected in series.

3.3 Hue Binning (Orange Chip Color)

The orange color is precisely controlled using six hue bins (S1 through S6) defined by quadrilaterals on the CIE 1931 chromaticity diagram. Each bin has specific (x, y) coordinate boundaries (e.g., S1: x 0.274-0.294, y 0.226-0.286). The tolerance for the chromaticity coordinates (x, y) within each hue bin is ±0.01. This ensures very tight color consistency for applications where precise orange hue is critical.

4. Performance Curve Analysis

The datasheet references typical characteristic curves which are essential for understanding device behavior under non-standard conditions. While the specific graphs are not fully detailed in the provided text, standard LED curves would typically include:

• Forward Current vs. Forward Voltage (I-V Curve): Shows the exponential relationship. The curve will differ between the InGaN (white) and AlInGaP (orange) chips due to their different semiconductor bandgaps, explaining the different typical V_F values.
• Luminous Intensity vs. Forward Current (I-L Curve): Demonstrates how light output increases with current, typically in a sub-linear manner at higher currents due to thermal and efficiency droop.
• Luminous Intensity vs. Ambient Temperature: Shows the decrease in light output as the junction temperature rises. This is critical for thermal management design.
• Spectral Power Distribution: For the orange chip, this graph would show the emission peak around 611 nm with the specified 20 nm half-width, confirming the color characteristics.

5. Mechanical & Package Information

5.1 Package Dimensions and Pin Assignment

The device uses a standard EIA package outline. Key dimensional tolerances are ±0.10 mm unless otherwise noted. The pin assignment for the dual-color function is clearly defined:

• Pins 1 and 3: Anode/Cathode for the InGaN White chip.
• Pins 2 and 4: Anode/Cathode for the AlInGaP Orange chip.

This 4-pin configuration allows independent control of the two colors. The lens material is specified as yellow, which may act as a diffuser or wavelength converter for the white chip and may slightly tint the orange output.

5.2 Suggested Soldering Pad Layout

The datasheet includes a recommended land pattern (solder pad dimensions) for PCB design. Following this guideline ensures proper solder joint formation during reflow, good mechanical stability, and optimal thermal dissipation from the LED package into the PCB.

6. Soldering & Assembly Guidelines

6.1 Reflow Soldering Process

The LED is compatible with infrared (IR) reflow soldering processes. The maximum condition it can withstand is 260°C for 10 seconds, which is standard for Pb-free assembly. A suggested reflow profile is implied, which typically includes a preheat zone, a rapid thermal ramp to peak temperature, a brief time above liquidus, and a controlled cooling phase. Adhering to this profile prevents thermal shock and solder defects.

6.2 Storage and Handling

• Sealed Package: Store at ≤30°C and ≤90% RH. Use within one year when the moisture-proof bag with desiccant is intact.
• Opened Package: For components removed from their sealed bag, the storage environment should not exceed 30°C / 60% RH. It is strongly recommended to complete the IR reflow process within one week of opening.
• Extended Storage (Opened): If storage exceeds one week, LEDs should be kept in a sealed container with desiccant or in a nitrogen desiccator. Components stored out of bag for more than a week require a baking pre-treatment (approximately 60°C for at least 20 hours) before soldering to remove absorbed moisture and prevent "popcorning" during reflow.

6.3 Cleaning

If post-assembly cleaning is necessary, only use specified solvents. Immersing the LED in ethyl alcohol or isopropyl alcohol at normal temperature for less than one minute is acceptable. The use of unspecified chemical cleaners is prohibited as they may damage the LED's epoxy lens or package.

7. Packaging & Ordering Information

7.1 Tape and Reel Specifications

The product is supplied in an industry-standard embossed carrier tape with a protective cover tape, wound onto a 7-inch (178 mm) diameter reel.

• Quantity per Reel: 3000 pieces.
• Minimum Order Quantity (MOQ): 500 pieces for remainder quantities.
• Tape Width: 8 mm.
• Packaging Standards: Complies with ANSI/EIA-481-1-A-1994 specifications for component packaging.
• Quality: The maximum number of consecutive missing components (empty pockets) in the tape is two.

Detailed dimensional drawings for both the carrier tape (pocket spacing, depth) and the reel (hub diameter, flange diameter) are provided for compatibility with automated equipment feeders.

8. Application Suggestions

8.1 Typical Application Scenarios

• Bi-Color Status Indicators: Ideal for equipment panels where a single LED can show multiple states (e.g., white for "on/active," orange for "standby/warning").
• Consumer Electronics Backlighting: Can be used for button or accent lighting in devices where dual-color effects are desired.
• Automotive Interior Lighting: For ambient lighting that can switch between white and orange tones.
• Industrial Control Panels: Providing clear, bright status indication in various operating modes.

8.2 Design Considerations

• Current Limiting: Always use a series current-limiting resistor or a constant-current driver for each chip. Calculate based on the supply voltage and the maximum forward voltage (V_{F MAX}) at the desired operating current (not exceeding I_F DC).
• Thermal Management: Although power dissipation is low, ensuring adequate PCB copper area around the solder pads helps conduct heat away, maintaining luminous output and longevity, especially at higher ambient temperatures or drive currents.
• ESD Protection: Incorporate ESD protection diodes on signal lines driving the LED in environments prone to static discharge.
• Optical Design: The 130-degree viewing angle provides wide coverage. For more directed light, secondary optics (lenses, light guides) may be required.

9. Technical Comparison & Differentiation

The LTW-C195DSKF-5A offers specific advantages in its class:

• Dual-Chip Integration: Combines two different semiconductor technologies (InGaN for white, AlInGaP for orange) in one package, offering superior color performance and brightness for each color compared to a single-chip LED with a phosphor covering that attempts two colors.
• Independent Control: Separate anodes/cathodes allow completely independent driving and dimming of each color, enabling dynamic color mixing or sequencing not possible with common-cathode/anode bi-color LEDs.
• High-Brightness Orange: The use of AlInGaP technology for the orange chip typically yields higher efficiency and brighter output at specific wavelengths compared to older technologies.
• Robust Packaging: Compatibility with IR reflow and tape-and-reel packaging makes it suitable for fully automated, high-volume surface-mount assembly lines.

10. Frequently Asked Questions (Based on Technical Parameters)

Q1: Can I drive both the white and orange chips simultaneously at their maximum DC current?
A: Not necessarily. You must consider the total power dissipation. Simultaneously driving White at 20mA (~2.75V) and Orange at 30mA (~2.00V) gives a combined power of ~112.5 mW, which may exceed the thermal design limits of the small package if there is insufficient heat sinking. It's safer to operate below absolute maximums or implement thermal derating.

Q2: What is the difference between Peak Wavelength and Dominant Wavelength?
A: Peak Wavelength (λ_P=611 nm) is the physical peak of the light spectrum the LED emits. Dominant Wavelength (λ_d=605 nm) is the perceptual peak—the single wavelength of pure spectral light that the human eye would match to the LED's color. They often differ, especially for broader spectra.

Q3: Why is the storage humidity requirement stricter for opened packages?
A: The epoxy molding compound used in SMD LEDs can absorb moisture from the air. During the high-temperature reflow soldering process, this trapped moisture can vaporize rapidly, creating internal pressure that can crack the package ("popcorning"). The baking process before soldering drives out this absorbed moisture.

Q4: How do I interpret the Hue Bin coordinates (e.g., S1)?
A: The four (x,y) coordinate pairs for a bin like S1 define the corners of a quadrilateral on the CIE chromaticity diagram. Any LED whose measured chromaticity coordinates fall within this quadrilateral is assigned to the S1 bin. This is a more precise method than simple wavelength bins for defining color space.

11. Practical Design Case Study

Scenario: Designing a multi-state power button for a consumer audio amplifier. The button needs to indicate: Off (dark), Standby (pulsing orange), On (steady white).

Implementation with LTW-C195DSKF-5A:
1. The LED is placed behind a translucent button cap.
2. A microcontroller (MCU) drives the two colors via two separate GPIO pins, each with its own series current-limiting resistor calculated for 5mA drive (for long life and moderate brightness).
3. Off State: Both MCU pins are set to high-impedance input or output low.
4. Standby State: The MCU's pin connected to the Orange LED (Pins 2/4) is driven with a PWM (Pulse-Width Modulation) signal to create a pulsing effect. The White LED pin remains off.
5. On State: The MCU pin for the White LED (Pins 1/3) is driven high continuously. The Orange LED pin is off.

This design uses only one component footprint, simplifies assembly, and provides clear, distinct visual feedback using high-quality, consistent light from both chips.

12. Technology Principle Introduction

The LTW-C195DSKF-5A utilizes two distinct solid-state lighting technologies:

• InGaN (White Chip): Typically, a blue-emitting InGaN LED chip is combined with a yellow phosphor coating (YAG:Ce). Some blue light escapes, and the rest is down-converted by the phosphor to yellow light. The mixture of blue and yellow light is perceived by the human eye as white. The yellow package lens may also contribute to color mixing or diffusion.
• AlInGaP (Orange Chip): This material system is grown on a substrate (often GaAs) and is engineered to have a direct bandgap corresponding to light emission in the red, orange, and yellow regions of the spectrum (roughly 590-650 nm). It is highly efficient for producing saturated colors in this range. The orange output is generated directly by electron-hole recombination within the semiconductor material itself, without phosphors.

Electroluminescence is the core principle: when a forward voltage is applied across the p-n junction of the semiconductor, electrons and holes recombine, releasing energy in the form of photons (light). The wavelength (color) of the light is determined by the bandgap energy of the semiconductor material.

13. Development Trends

The field of SMD LEDs continues to evolve, with trends that contextualize devices like the LTW-C195DSKF-5A:

• Increased Efficiency and Luminous Flux: Ongoing improvements in epitaxial growth, chip design, and package extraction efficiency lead to higher mcd output per mA of input current, allowing for lower power consumption or brighter displays.
• Miniaturization: While this is a standard EIA package, the industry pushes for smaller footprints (e.g., 0402, 0201) for ultra-compact devices, though often at the expense of total light output or thermal performance.
• Improved Color Consistency and Binning: Advances in manufacturing process control yield tighter distributions in V_F, I_V, and chromaticity, reducing the number of bins needed and ensuring more uniform performance in batch production.
• Integrated Solutions: A trend towards LEDs with built-in current regulators, ESD protection, or even simple control logic ("smart LEDs") to simplify circuit design for the end user.
• Focus on Reliability and Lifetime: Enhanced materials for lenses and encapsulants that offer better resistance to heat, humidity, and short-wavelength light, leading to longer operational lifespans, especially important for industrial and automotive applications.