SMT CBI Bicolor LED Indicator LTL-M12YB1H310U - Yellow/Blue - 10mA - 72/78mW - English Datasheet

1. Product Overview

The LTL-M12YB1H310U is a Surface Mount Technology (SMT) Circuit Board Indicator (CBI). It consists of a black plastic right-angle housing designed to mate with specific LED lamps. This component is engineered for ease of assembly onto printed circuit boards (PCBs), offering a stackable design for creating horizontal or vertical arrays. The primary function is to provide a clear, high-contrast visual status indication in electronic equipment.

1.1 Core Features and Advantages

• Surface Mount Design: Fully compatible with automated SMT assembly processes, enabling high-volume, efficient PCB population.
• Enhanced Visibility: The black housing material provides a high contrast ratio against the illuminated LED, improving readability in various lighting conditions.
• Dual Color Source: Integrates AlInGaP (Aluminum Indium Gallium Phosphide) for yellow emission and InGaN (Indium Gallium Nitride) for blue emission, combined with a white diffused lens for a uniform light appearance.
• Energy Efficiency: Characterized by low power consumption and high luminous efficiency, suitable for power-sensitive applications.
• Environmental Compliance: This is a lead-free product and complies with the RoHS (Restriction of Hazardous Substances) directive.
• Reliability Testing: Devices undergo preconditioning accelerated to JEDEC (Joint Electron Device Engineering Council) Level 3 standards, indicating a robust moisture sensitivity level suitable for standard SMT reflow processes.

1.2 Target Applications and Markets

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

• Computer Systems: Status lights on motherboards, servers, storage devices, and peripherals.
• Communication Equipment: Indicators for network switches, routers, modems, and telecommunication devices.
• Consumer Electronics: Power, mode, or function indicators in audio/video equipment, home appliances, and personal devices.
• Industrial Controls: Panel indicators for machinery, instrumentation, and control systems requiring reliable visual feedback.

2. Technical Specifications and Objective Interpretation

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 (P_d): Yellow: 72 mW, Blue: 78 mW. This parameter limits the total electrical power that can be converted into heat within the LED package.
• Peak Forward Current (I_FP): 80 mA for both colors. This is the maximum allowable instantaneous current, typically for pulsed operation with a duty cycle ≤ 1/10 and pulse width ≤ 0.1ms. Exceeding this can cause catastrophic failure.
• DC Forward Current (I_F): Yellow: 30 mA, Blue: 20 mA. This is the maximum continuous current recommended for reliable long-term operation. The lower rating for the blue LED reflects typical material characteristics of InGaN.
• Temperature Ranges: Operating: -40°C to +85°C; Storage: -40°C to +100°C. These wide ranges ensure functionality in harsh environments and safe storage conditions.

2.2 Electrical and Optical Characteristics

These are typical performance parameters measured at an ambient temperature (T_A) of 25°C under specified test conditions.

• Luminous Intensity (I_V): Yellow: 18 mcd (min), Blue: 12.6 mcd (min) at I_F = 10mA. This measures the perceived brightness by the human eye. The classification code for I_V is marked on the packing bag for binning purposes.
• Peak Emission Wavelength (λ_P): Yellow: 592 nm (typ), Blue: 468 nm (typ). This is the wavelength at which the spectral power output is maximum.
• Dominant Wavelength (λ_d): Yellow: 582-595 nm, Blue: 464-476 nm at I_F = 10mA. Derived from the CIE chromaticity diagram, this single wavelength best represents the perceived color of the LED and defines its color bin.
• Spectral Line Half-Width (Δλ): Yellow: 15 nm (typ), Blue: 25 nm (typ). This indicates the spectral purity; a smaller value means a more monochromatic light. Yellow AlInGaP LEDs typically have narrower spectra than blue InGaN LEDs.
• Forward Voltage (V_F): Yellow: 1.7-2.4V, Blue: 2.7-3.8V at I_F = 10mA. The voltage drop across the LED when conducting current. The higher V_F for blue is characteristic of InGaN technology.
• Reverse Current (I_R): 10 µA (max) for both colors at V_R = 5V. LEDs are not designed for reverse bias operation; this parameter is for leakage test purposes only.

3. Binning System Explanation

The datasheet implies a binning system based on key optical parameters to ensure color and brightness consistency in production.

• Wavelength/Color Binning: The dominant wavelength (λ_d) ranges (Yellow: 582-595nm, Blue: 464-476nm) define the acceptable color variation. Products are sorted into bins within these ranges.
• Luminous Intensity Binning: The luminous intensity (I_V) has a minimum specified value. Devices are likely tested and classified into intensity bins, with the specific bin code marked on the packaging (as noted in the datasheet).
• Forward Voltage Binning: While not explicitly stated as a binned parameter, the specified V_F range indicates the permissible variation. Consistent V_F is important for current matching in parallel circuits.

4. Performance Curve Analysis

The datasheet references typical characteristic curves which are essential for design.

• I-V (Current-Voltage) Curve: Shows the relationship between forward current (I_F) and forward voltage (V_F). It is non-linear, with a turn-on/threshold voltage (approx. 1.5V for yellow, 2.5V for blue) after which current increases rapidly with small voltage increases. This necessitates current-limiting in drive circuits.
• Luminous Intensity vs. Forward Current: Typically shows I_V increasing linearly with I_F at lower currents, potentially saturating at higher currents due to thermal and efficiency droop.
• Temperature Dependence: Luminous intensity generally decreases with increasing junction temperature. Forward voltage also decreases with rising temperature (negative temperature coefficient).
• Spectral Distribution: The graph would show the relative radiant power versus wavelength, with a peak at λ_P and a width defined by Δλ. The dominant wavelength λ_d is calculated from this spectrum.

5. Mechanical and Package Information

5.1 Outline Dimensions

The component features a right-angle (90-degree) mounting profile. Key dimensional notes include:

• All dimensions are in millimeters, with a default tolerance of ±0.25mm unless otherwise specified.
• The housing material is black plastic.
• The integrated LED is a yellow/blue bicolor type with a white diffused lens for light mixing and wider viewing angle.

5.2 Polarity Identification and Mounting

While the exact pad layout isn't detailed in the provided text, SMT LEDs require correct polarity orientation. The PCB footprint design must match the component's lead configuration. The black housing and right-angle design aid in mechanical alignment during placement.

6. Soldering and Assembly Guidelines

6.1 Storage and Handling

• Sealed Package: Store at ≤30°C and ≤70% RH. Use within one year of the bag seal date.
• Opened Package: For components removed from moisture barrier bags, store at ≤30°C and ≤60% RH. It is recommended to complete IR reflow soldering within 168 hours (1 week) of exposure.
• Extended Exposure: If exposure exceeds 168 hours, a bake-out at approximately 60°C for at least 48 hours is required before soldering to remove absorbed moisture and prevent \"popcorning\" damage during reflow.

6.2 Soldering Process Parameters

• Hand Soldering (Iron): Maximum temperature 350°C, maximum time 3 seconds per joint. Apply only once.
• Wave Soldering: Pre-heat: 150-200°C for up to 120 seconds. Solder wave: Maximum 260°C for up to 5 seconds. Process maximum is two times.
• Reflow Soldering: The component is qualified for JEDEC Level 3. A sample reflow profile is provided, emphasizing the need to follow JEDEC limits and solder paste manufacturer recommendations. The reflow process must not exceed two cycles. The profile typically includes preheat, thermal soak, reflow peak (recommended ~245-260°C), and cooling stages.

6.3 Cleaning and Mechanical Stress

• Use alcohol-based solvents like isopropyl alcohol for cleaning if necessary.
• Avoid applying mechanical stress to the leads or housing during assembly. Do not use the lead frame base as a fulcrum for bending.

7. Packaging and Ordering Information

7.1 Packing Specification

• Carrier Tape: Standard 10-sprocket-hole pitch design. Material: Black Conductive Polystyrene Alloy. Thickness: 0.40 ±0.06 mm.
• Reel: Standard 13-inch (330mm) diameter reel. Quantity: 1,400 pieces per reel.
• Carton: One reel is packed with a desiccant and humidity indicator card in a Moisture Barrier Bag (MBB). Three MBBs are packed in an Inner Carton (4,200 pcs total). Ten Inner Cartons are packed in an Outer Carton (42,000 pcs total).

7.2 Part Number and Revision

The base part number is LTL-M12YB1H310U. The document revision history is tracked, with the effective date of the current specification being 04/01/2021.

8. Application Design Recommendations

8.1 Drive Circuit Design

Critical Consideration: LEDs are current-driven devices. To ensure uniform brightness, especially when multiple LEDs are connected in parallel, a series current-limiting resistor must be used for each LED (Circuit Model A). Driving multiple LEDs in parallel directly from a voltage source (Circuit Model B) is not recommended, as small variations in individual LED forward voltage (V_F) will cause significant differences in current and, consequently, brightness.

The series resistor value (R_s) can be calculated using Ohm's Law: R_s = (V_supply - V_F) / I_F, where I_F is the desired operating current (e.g., 10mA) and V_F is the typical forward voltage from the datasheet.

8.2 Thermal Management

While power dissipation is low, maintaining the LED junction temperature within the specified operating range is crucial for long-term reliability and stable light output. Ensure adequate PCB copper area or thermal relief around the solder pads to dissipate heat, especially if operating near the maximum DC current.

9. Technical Comparison and Differentiation

Compared to discrete LED chips or simpler SMT LEDs, this CBI (Circuit Board Indicator) offers distinct advantages:

• Integrated Solution: Combines the LED chip, lens, and a structural right-angle housing in one SMT package, simplifying mechanical design and assembly.
• Enhanced Readability: The black housing and diffused lens provide superior contrast and viewing angle compared to many clear-lens, non-housed LEDs.
• Bicolor Functionality: The integration of two distinct semiconductor materials (AlInGaP and InGaN) in one package allows for dual-status indication (e.g., power on/standby, mode A/mode B) without using additional PCB space.
• Stackable Design: Facilitates the creation of multi-indicator bars or arrays with consistent spacing and alignment.

10. Frequently Asked Questions (FAQ)

Q1: Can I drive this LED directly from a 5V or 3.3V logic output?
A1: No. You must use a series current-limiting resistor. For example, with a 5V supply and the blue LED (V_F ~3.2V typ) at 10mA: R_s = (5V - 3.2V) / 0.01A = 180 Ω. A driver transistor or dedicated LED driver IC may be needed for higher currents or multiplexing.

Q2: What is the difference between Peak Wavelength (λ_P) and Dominant Wavelength (λ_d)?
A2: λ_P is the physical peak of the light spectrum. λ_d is a calculated value that represents the perceived color by the human eye, derived from the full spectrum and the CIE color matching functions. λ_d is more relevant for color specification and binning.

Q3: How do I interpret the JEDEC Level 3 preconditioning?
A3: JEDEC Level 3 means the component can be exposed to factory ambient conditions (≤30°C/60% RH) for up to 168 hours (1 week) after the moisture barrier bag is opened without requiring a bake before reflow soldering. This offers flexibility in manufacturing scheduling.

Q4: Why are the maximum currents different for yellow and blue?
A4: The different semiconductor materials (AlInGaP vs. InGaN) have different electrical and thermal properties, leading to different maximum safe operating current densities as defined by the manufacturer's reliability testing.

11. Practical Application Example

Scenario: Designing a status panel for a network switch. The panel needs a green light for \"Link Active,\" a yellow light for \"Activity,\" and a blue light for \"PoE (Power over Ethernet) Active.\" While this specific part is yellow/blue, similar CBI components in green could be used. The designer would:

1. Place three CBI footprints (for green, yellow, blue) in a vertical array on the PCB front panel area.
2. For each LED, calculate the appropriate series resistor based on the system's 3.3V digital I/O voltage and the desired 8mA drive current for adequate brightness.
3. Route the control signals from the switch's main microcontroller to the current-limiting resistors and then to the LED anodes. Connect all cathodes to ground.
4. In the assembly instructions, specify that the SMT line must follow the JEDEC Level 3 reflow profile and that any boards with exposed CBIs for more than 168 hours before soldering must be baked.

This approach yields a professional, consistent-looking indicator panel that is easy to assemble automatically.

12. Operating Principle Introduction

Light Emitting Diodes (LEDs) are semiconductor p-n junction devices. When a forward voltage is applied, electrons from the n-type region and holes from the p-type region are injected into the junction region (the active layer). There, they recombine, releasing energy. In these materials (AlInGaP and InGaN), this energy is released primarily as photons (light) – a process called electroluminescence. The specific color (wavelength) of the emitted light is determined by the bandgap energy of the semiconductor material used in the active layer. AlInGaP has a bandgap corresponding to red, orange, and yellow light, while InGaN can produce light from green into the ultraviolet, with blue being a common output. The white diffused lens scatters the light, creating a more uniform and wider viewing angle.

13. Technology Trends

The development of SMT indicators like the CBI follows broader trends in electronics:

• Miniaturization and Integration: Continued reduction in package size and integration of more features (e.g., RGB multi-color, built-in IC drivers) into single SMT packages.
• Higher Efficiency: Ongoing improvements in internal quantum efficiency (IQE) and light extraction techniques lead to higher luminous intensity per unit of electrical input power.
• Improved Reliability and Robustness: Advancements in packaging materials and die attach technologies enhance performance over wider temperature ranges and longer lifetimes.
• Standardization: Wider adoption of standardized footprints and optical characteristics to simplify design and sourcing for engineers.