SMT CBI Bicolor LED Indicator LTL-M12YG1H310U Datasheet - Yellow Green/Yellow - 10mA - English Technical Document

1. Product Overview

The LTL-M12YG1H310U is a Surface Mount Technology (SMT) Circuit Board Indicator (CBI). It consists of a black plastic right-angle holder (housing) designed to mate with specific LED lamps. This design facilitates easy assembly onto printed circuit boards (PCBs). The primary function is to provide a clear, high-contrast visual status indication. The unit features a bicolor LED source, capable of emitting either Yellow Green or Yellow light through a white diffused lens, which helps in achieving a uniform illumination appearance.

1.1 Core Features and Advantages

• Surface Mount Design: Optimized for automated pick-and-place and reflow soldering processes, enhancing manufacturing efficiency and reliability.
• High Contrast Housing: The black plastic case significantly improves the contrast ratio of the emitted light, making the indicator more visible, especially in bright ambient lighting conditions.
• Bicolor Functionality: Integrates Yellow Green and Yellow LED chips in a single package, allowing for dual-state indication (e.g., standby/active, normal/warning) using one component footprint.
• Energy Efficiency: Characterized by low power consumption and high luminous efficiency, making it suitable for power-sensitive applications.
• Environmental Compliance: This is a lead-free product and complies with the Restriction of Hazardous Substances (RoHS) directive.
• Robust Construction: Designed to withstand standard SMT assembly processes, including preconditioning accelerated to JEDEC Moisture Sensitivity Level 3.

1.2 Target Applications and Markets

This indicator is designed for use in ordinary electronic equipment across several key industries:

• Computer Systems: Status lights for power, storage activity, or network connectivity on motherboards, servers, and peripherals.
• Communication Equipment: Indicator lights on routers, switches, modems, and other networking hardware.
• Consumer Electronics: Power, mode, or function indicators in appliances, audio/video equipment, and home automation devices.
• Industrial Controls: Status and fault indicators on control panels, machinery, and instrumentation where reliable visual feedback is required.

2. In-Depth Technical Parameter Analysis

All parameters are specified at an ambient temperature (TA) of 25°C unless otherwise noted. Understanding these limits is critical for reliable circuit design.

2.1 Absolute Maximum Ratings

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

• Power Dissipation (PD): 72 mW (for each color, Yellow Green and Yellow). This is the maximum allowable power loss as heat.
• Peak Forward Current (IFP): 80 mA. This current is permissible only under pulsed conditions (duty cycle ≤ 1/10, pulse width ≤ 0.1ms) for very short durations.
• Continuous DC Forward Current (IF): 30 mA. This is the maximum recommended current for continuous operation.
• Operating Temperature Range: -40°C to +85°C. The device is guaranteed to function within this ambient temperature range.
• Storage Temperature Range: -40°C to +100°C. The device can be stored without damage within these limits.

2.2 Electrical and Optical Characteristics

These are the typical performance parameters under standard test conditions (IF = 10mA).

• Luminous Intensity (Iv):
  • Yellow Green: Typical 8.7 mcd (Min 4.5 mcd, Max 23 mcd).
  • Yellow: Typical 15 mcd (Min 4.5 mcd, Max 23 mcd).
  • Iv classification code is marked on each packing bag for binning purposes.
  • Measurement is performed with a sensor/filter approximating the CIE photopic eye-response curve.
• Viewing Angle (2θ1/2): 40 degrees for both colors. This is the full angle at which the luminous intensity drops to half of its peak axial value, defining the beam spread.
• Peak Wavelength (λP):
  • Yellow Green: 574 nm.
  • Yellow: 592 nm.
  • This is the wavelength at the highest point in the emitted spectrum.
• Dominant Wavelength (λd):
  • Yellow Green: 570 nm (range 564-574 nm).
  • Yellow: 590 nm (range 584-596 nm).
  • This is the single wavelength perceived by the human eye, derived from the CIE chromaticity diagram.
• Spectral Half-Width (Δλ): Approximately 15 nm for both colors, indicating the spectral purity.
• Forward Voltage (VF): 2.5 V typical (2.0 V min) at 10mA for both colors. This parameter is crucial for current-limiting resistor calculation.
• Reverse Current (IR): 10 μA maximum when a reverse voltage (VR) of 5V is applied. Important: This device is not designed for operation under reverse bias; this test condition is for characterization only.

3. Binning and Classification System

The product employs a classification system to ensure consistency in key optical parameters.

• Luminous Intensity (Iv) Binning: The Iv value is classified, and the corresponding code is printed on each packing bag. This allows designers to select components within a specific brightness range for uniform panel appearance.
• Wavelength Binning: The dominant wavelength (λd) is specified with a range (e.g., 564-574 nm for Yellow Green). Components are sorted to fall within these chromaticity limits.
• Forward Voltage: While a typical value is given, the min/max range (2.0V to 2.5V at 10mA) defines the acceptable variation for this parameter.

4. Performance Curve Analysis

Typical performance curves (referenced in the datasheet) provide visual insight into device behavior under varying conditions. Designers should consult these graphs for detailed analysis.

• Relative Luminous Intensity vs. Forward Current: This curve shows how light output increases with current. It is typically non-linear, and operating above the recommended DC current may not yield proportional brightness gains while increasing heat and reducing lifespan.
• Forward Voltage vs. Forward Current: This IV characteristic curve is essential for understanding the dynamic resistance of the LED and for designing an appropriate drive circuit.
• Relative Luminous Intensity vs. Ambient Temperature: LED light output generally decreases as junction temperature rises. This curve helps estimate brightness derating in high-temperature environments.
• Spectral Distribution: Graphs showing the relative intensity across wavelengths for each color, centered around their peak wavelengths (574 nm and 592 nm).

5. Mechanical and Package Information

5.1 Outline Dimensions

The device is housed in a black plastic right-angle holder. Key dimensional notes:

• All primary dimensions are provided in millimeters, with a default tolerance of ±0.25mm unless otherwise specified.
• The housing material is black plastic.
• The integrated LED is a bicolor (Yellow Green/Yellow) type with a white diffused lens.
• Detailed dimensional drawings should be consulted for precise PCB footprint and placement planning.

5.2 Polarity Identification and Mounting

As an SMT component, correct orientation during placement is vital. The datasheet's footprint diagram indicates the cathode and anode pads. Designers must ensure the PCB footprint matches this diagram to prevent incorrect placement by automated machinery.

6. Soldering and Assembly Guidelines

Adherence to these guidelines is critical to prevent damage during the assembly process.

6.1 Storage and Handling

• Sealed Package: Store at ≤30°C and ≤70% RH. Use within one year of the pack date.
• Opened Package: If the Moisture Barrier Bag (MBB) is opened, the storage environment must not exceed 30°C and 60% RH.
• Floor Life: Components exposed to ambient air should undergo IR reflow soldering within 168 hours (7 days).
• Rebaking: If exposed for more than 168 hours, a bake at 60°C for at least 48 hours is required before soldering to remove absorbed moisture and prevent \"popcorning\" during reflow.

6.2 Soldering Process

• Reflow Soldering (Recommended): A JEDEC-compliant reflow profile must be used.
  • Preheat/Soak: 150-200°C for up to 100 seconds max.
  • Time Above Liquidous (T_L=217°C): 60-150 seconds.
  • Peak Temperature (T_P): 260°C maximum.
  • Time within 5°C of Specified Classification Temp (T_C=255°C): 30 seconds maximum.
  • Total time from 25°C to peak: 5 minutes maximum.
• Hand Soldering: If necessary, use a soldering iron at a maximum temperature of 300°C for no more than 3 seconds per joint. Avoid applying mechanical stress to the leads during soldering.
• Cleaning: Use only alcohol-based solvents like isopropyl alcohol (IPA). Avoid aggressive or unknown chemical cleaners.

Critical Note: The maximum reflow temperature is not an indicator of the holder's Heat Deflection Temperature (HDT) or melting point. Exceeding time/temperature limits can deform the plastic lens or cause catastrophic LED failure.

7. Packaging and Ordering Information

7.1 Packaging Specification

• Carrier Tape: Components are supplied on 13-inch reels. The carrier tape is made of black conductive polystyrene alloy, 0.40mm thick.
• Quantity per Reel: 1,400 pieces.
• Humidity Protection: Each reel is packed with a desiccant and a humidity indicator card inside a Moisture Barrier Bag (MBB).
• Inner Carton: Contains 3 MBBs (total 4,200 pieces).
• Outer Carton: Contains 10 inner cartons (total 42,000 pieces).

7.2 Model Number Interpretation

The part number LTL-M12YG1H310U can be interpreted as part of a family coding system, though the full breakdown is proprietary. It identifies this specific SMT CBI variant with bicolor Yellow Green/Yellow output.

8. Application Design Considerations

8.1 Drive Circuit Design

LEDs are current-driven devices. A series current-limiting resistor is mandatory when driving from a voltage source. The resistor value (R_series) can be calculated using Ohm's Law: R_series = (V_supply - V_F) / I_F. Use the maximum V_F from the datasheet for a conservative design to ensure the current does not exceed the desired level. For example, to drive at 10mA from a 5V supply: R = (5V - 2.5V) / 0.01A = 250 Ω. A 270 Ω standard value resistor would be a safe choice.

8.2 Thermal Management

While the power dissipation is low (72mW), ensuring a proper PCB layout can help manage heat. Connect the thermal pads (if present in the footprint) to a copper area to act as a heat sink. Avoid placing the indicator near other significant heat sources on the board.

8.3 Optical Integration

The 40-degree viewing angle provides a reasonably wide beam. The white diffused lens creates a uniform, soft glow rather than a sharp point source. The black housing prevents light piping and improves off-state appearance. Consider these factors when designing light pipes or panel cutouts.

9. Comparison and Differentiation

The LTL-M12YG1H310U offers specific advantages in its category:

• vs. Single-Color SMT LEDs: Provides two distinct colors (Yellow Green and Yellow) in one package, saving PCB space and assembly cost compared to using two separate single-color LEDs for dual-state indication.
• vs. Through-Hole LEDs: The SMT design eliminates the need for drilling holes, allows for higher-density PCB layouts, and is compatible with fully automated assembly lines, reducing manufacturing cost and time.
• vs. Un-diffused LEDs: The integrated white diffused lens offers a more uniform and aesthetically pleasing light spot compared to LEDs with clear lenses, which can exhibit a more pronounced \"hot spot.\"

10. Frequently Asked Questions (FAQ)

Q1: Can I drive this LED at 20mA continuously?
A1: The Absolute Maximum Rating for DC forward current is 30mA. While driving at 20mA is within this limit, you must refer to the \"Relative Luminous Intensity vs. Forward Current\" curve. The increase in light output from 10mA to 20mA may be sub-linear, and the increased power dissipation (heat) could reduce longevity. Operating at the typical test condition of 10mA is recommended for optimal lifespan.

Q2: How do I control the two colors independently?
A2: The datasheet implies a common-cathode or common-anode configuration for the two chips inside the package. The schematic in the footprint diagram will show the pinout. You will need two separate current-limiting resistors and drive circuits (e.g., microcontroller GPIO pins) to control each color channel independently.

Q3: Is the 168-hour floor life after opening the bag a strict requirement?
A3: Yes, it is critical for reliability. Exposure beyond 168 hours allows moisture to absorb into the plastic package. During reflow, this moisture can vaporize rapidly, causing internal delamination or cracking (\"popcorning\"). If exceeded, the mandatory 48-hour bake at 60°C must be performed.

Q4: What is the difference between Peak Wavelength and Dominant Wavelength?
A4: Peak Wavelength (λP) is the physical wavelength at the highest intensity point on the spectral output graph. Dominant Wavelength (λd) is a calculated value based on human color perception (CIE chart) and represents the \"color\" we actually see. For LEDs, these values are often close but not identical.

11. Design and Usage Case Study

Scenario: Designing a status panel for a network router.
A designer needs indicators for \"Power On\" (steady), \"System Activity\" (blinking), and \"Ethernet Link/Activity\" (dual-state). They could use:
- A single-color Green LED for \"Power On.\"
- A single-color Amber LED blinking for \"System Activity.\"
- One LTL-M12YG1H310U bicolor LED for \"Ethernet.\" It can show a steady Yellow Green for a 100Mbps link, a steady Yellow for a 1Gbps link, and blink the respective color during data activity. This solution uses only three component footprints to convey four distinct states, optimizing panel space and simplifying the bill of materials compared to using four separate single-color LEDs.

12. Technical Principle Introduction

Light Emitting Diodes (LEDs) are semiconductor devices that emit light through electroluminescence. When a forward voltage is applied across the p-n junction, electrons recombine with holes, releasing energy in the form of photons. The specific wavelength (color) of the emitted light is determined by the energy bandgap of the semiconductor materials used (e.g., Gallium Arsenide Phosphide (GaAsP) alloys for yellow and yellow-green colors). The white diffused lens contains scattering particles that randomize the direction of the emitted photons, creating a more uniform and wider viewing angle compared to a clear lens.

13. Industry Trends and Developments

The market for SMT indicators continues to evolve. Trends include:
Miniaturization: Development of even smaller package sizes (e.g., 0402, 0201 metric) for ultra-high-density boards.
Increased Efficiency: Ongoing improvements in epitaxial materials and chip design yield higher luminous intensity (mcd) at lower drive currents, reducing overall system power consumption.
Integrated Solutions: Growth of LEDs with built-in current-limiting resistors or IC drivers (\"smart LEDs\") to simplify circuit design.
Color Options: Expansion of available colors and multi-color combinations (RGB, RGBW) in single packages for more versatile aesthetic and status indication applications.
The LTL-M12YG1H310U fits into the trend of providing multi-functionality (bicolor) in a standard, reliable, and manufacturable SMT package.