SMT CBI Blue LED LTL-M11TB1H310Q Datasheet - Dimensions 3.0x2.0x1.6mm - Voltage 3.8V - Power 80mW - Blue/White

1. Product Overview

The LTL-M11TB1H310Q is a Surface Mount Technology (SMT) Circuit Board Indicator (CBI). It consists of a black plastic right-angle holder (housing) designed to mate with a specific LED lamp. The primary function is to provide a highly visible status or indicator light on printed circuit boards (PCBs). The device utilizes a blue InGaN (Indium Gallium Nitride) semiconductor chip. The emitted blue light passes through a white diffused lens, which scatters the light to create a wider, more uniform viewing area compared to a clear lens. The black housing material is chosen specifically to enhance the contrast ratio, making the illuminated indicator appear brighter against the dark background, especially in well-lit environments.

1.1 Core Advantages and Target Markets

The product is designed for integration into modern electronic assembly lines. Its key advantages include compatibility with automated pick-and-place and reflow soldering processes, leading to high-volume manufacturing efficiency. The stackable design of the housing allows for the creation of vertical or horizontal arrays of indicators in a compact footprint. The device is RoHS compliant and lead-free, meeting global environmental regulations. Primary target markets and applications include status indicators in computer peripherals and motherboards, signal and link indicators in communication equipment (routers, switches), display backlights or power indicators in consumer electronics, and panel indicators in industrial control systems and instrumentation.

2. Technical Parameter Analysis

This section provides a detailed, objective interpretation of the key electrical, optical, and thermal parameters defined in the datasheet, explaining their significance for design engineers.

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.

• Power Dissipation (Pd): 80 mW: This is the maximum amount of electrical power the LED package can safely convert into heat and light without exceeding its thermal limits. Exceeding this value risks overheating the semiconductor junction, leading to accelerated degradation or catastrophic failure.
• Peak Forward Current (I_FP): 100 mA: This is the maximum instantaneous current the LED can withstand under pulsed conditions (duty cycle ≤ 10%, pulse width ≤ 0.1ms). It is relevant for brief, high-intensity flashes but not for continuous operation.
• DC Forward Current (I_F): 20 mA: This is the maximum recommended continuous forward current for reliable long-term operation. The typical test condition for other parameters (like luminous intensity) is 10 mA, indicating a standard operating point that provides a good balance of brightness and longevity.
• Operating Temperature Range: -40°C to +85°C: The LED is rated to function correctly within this ambient temperature range. Performance at the extremes may deviate from the 25°C specifications.
• Soldering Temperature: 260°C for 5 seconds max.: This defines the maximum thermal profile the device can endure during reflow soldering without damage, aligning with common lead-free solder process requirements.

2.2 Electrical & Optical Characteristics

These are the typical performance parameters measured at TA=25°C and I_F=10mA, unless otherwise stated.

• Luminous Intensity (I_V): 8.7 (Min), 23 (Typ), 40 (Max) mcd: This measures the perceived brightness of the LED as seen by the human eye (photopic vision). The wide range (Min to Max) indicates a production binning process. The classification code marked on the packing bag corresponds to this intensity bin.
• Viewing Angle (2θ_1/2): 40° (Typ): Defined as the full angle at which the luminous intensity drops to half of its peak (on-axis) value. A 40° angle indicates a moderately focused beam, wider than a narrow spotlight but more directional than a fully diffused lamp. The white diffused lens is responsible for shaping this angle.
• Peak Emission Wavelength (λ_P): 468 nm (Typ): The specific wavelength at which the optical power output is greatest. This is a physical property of the InGaN chip.
• Dominant Wavelength (λ_d): 464-477 nm: This represents the single wavelength that best describes the perceived color of the LED to the human eye, derived from the CIE chromaticity diagram. The specified range (464-477 nm) defines the color bin for this product, ensuring a consistent blue hue across production lots.
• Spectral Line Half-Width (Δλ): 20 nm (Typ): The wavelength range over which the optical power is at least half of the peak power. A value of 20 nm is typical for a blue InGaN LED and indicates a relatively pure spectral color.
• Forward Voltage (V_F): 3.1 (Min), 3.8 (Typ) V: The voltage drop across the LED when driven at the specified current (10mA). This is crucial for designing the current-limiting circuitry. The variation is due to normal semiconductor manufacturing tolerances.
• Reverse Current (I_R): 10 µA max. at V_R=5V: LEDs are not designed for reverse bias operation. This parameter is for test purposes only. Applying a reverse voltage exceeding 5V can cause breakdown and damage the device.

3. Binning System Explanation

The datasheet implies a binning system to ensure consistency in key parameters for automated assembly and consistent end-product appearance.

3.1 Luminous Intensity Binning

The luminous intensity is classified into bins, with a code marked on each packing bag (Note 3). The specified range is from 8.7 mcd (minimum) to 40 mcd (maximum). Designers should select the appropriate bin based on the required brightness level for their application. Using LEDs from the same bin within a product ensures uniform indicator brightness.

3.2 Dominant Wavelength Binning

The dominant wavelength is binned between 464 nm and 477 nm. This tight control ensures that all LEDs designated as this part number will appear as the same shade of blue to the human eye, which is critical for applications where color consistency is important (e.g., multi-indicator panels).

4. Performance Curve Analysis

While the specific graphs are not reproduced in the text, the datasheet references typical curves which are standard for LED characterization.

4.1 Forward Current vs. Forward Voltage (I-V Curve)

The I-V curve for an LED is exponential. For the LTL-M11TB1H310Q, at the typical operating current of 10 mA, the forward voltage is approximately 3.8V. The curve shows that a small increase in voltage beyond the "turn-on" point results in a large increase in current. This highlights the critical need for a current-limiting device (resistor or constant-current driver) and why LEDs are considered current-operated devices.

4.2 Luminous Intensity vs. Forward Current

This curve is generally linear over a range. Luminous intensity increases proportionally with forward current. However, operating above the recommended DC current (20 mA) will lead to super-linear increase in heat generation and rapid degradation of light output (lumen depreciation).

4.3 Temperature Dependence

LED performance is temperature-sensitive. As the junction temperature increases:

• Forward Voltage (V_F) decreases slightly.
• Luminous Intensity (I_V) decreases. The exact relationship is defined by the thermal coefficient, which is not specified here but is a key consideration for high-reliability applications.
• Dominant Wavelength (λ_d) may shift slightly, potentially affecting perceived color at extreme temperatures.

5. Mechanical & Packaging Information

5.1 Outline Dimensions and Polarity

The device is a right-angle SMT component. The housing is made of black plastic. The LED itself is described as blue with a white diffused lens. Critical assembly notes include: all dimensions are in millimeters, with a standard tolerance of ±0.25mm unless otherwise specified. The polarity of the LED (anode/cathode) is indicated by the physical features of the housing or the internal die orientation, which must be aligned with the PCB footprint's polarity marking.

5.2 Tape and Reel Packaging

The device is supplied on embossed carrier tape for automated assembly. Key specifications:

• Carrier Tape: Made of black conductive polystyrene alloy, 0.40 ±0.06 mm thick.
• Reel Size: Standard 13-inch (330mm) reel.
• Quantity per Reel: 1,400 pieces.
• Packing Hierarchy: 1 reel is sealed in a Moisture Barrier Bag (MBB) with a desiccant and humidity indicator. 3 MBBs are packed in an inner carton (4,200 pcs total). 10 inner cartons are packed in an outer shipping carton (42,000 pcs total).

This packaging is designed for moisture sensitivity (MSL) and to prevent electrostatic discharge (ESD) due to the conductive tape.

6. Soldering & Assembly Guidelines

6.1 Storage and Handling

The LEDs are moisture-sensitive (MSL). When the sealed Moisture Barrier Bag (MBB) is unopened, they should be stored at ≤30°C and ≤70% RH, with a shelf life of one year. Once the MBB is opened, the components must be stored at ≤30°C and ≤60% RH. It is strongly recommended that components removed from the MBB be subjected to IR reflow soldering within 168 hours (7 days). If this time is exceeded, a bake-out at 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

The device is designed for reflow soldering. A sample JEDEC-compliant temperature profile is referenced. Key parameters from the datasheet:

• Reflow Soldering (Maximum): Peak temperature 260°C for 5 seconds.
• Pre-heat: 150-200°C for up to 120 seconds.
• Number of Reflows: Maximum of 2 times.

Hand soldering with an iron is permissible but must be limited to 300°C for a maximum of 3 seconds, and only performed once. No external stress should be applied to the leads during soldering while the LED is hot. Cleaning, if necessary, should use alcohol-based solvents like isopropyl alcohol.

6.3 Assembly Precautions

If any lead forming is required (though unlikely for a pure SMT part), it must be done before soldering and at a point at least 3mm from the base of the LED lens to avoid damaging the internal wire bonds or the epoxy lens. During placement on the PCB, minimal clinch force should be used to avoid mechanical stress on the package.

7. Application Design Considerations

7.1 Drive Circuit Design

The datasheet explicitly states: "An LED is a current-operated device." The recommended drive method is Circuit A, which includes a series current-limiting resistor for each LED. This is critical when connecting multiple LEDs in parallel. Due to natural variations in forward voltage (V_F), connecting LEDs directly in parallel without individual resistors (Circuit B) will cause current to unevenly distribute. The LED with the lowest V_F will draw more current, appearing brighter and potentially failing prematurely, while others may be dim. The series resistor ensures each LED receives a consistent current, guaranteeing uniform brightness and longevity. The resistor value is calculated using Ohm's Law: R = (V_supply - V_{F_LED}) / I_F.

7.2 Thermal Management

Although the power dissipation is low (80mW max), proper thermal design on the PCB contributes to long-term reliability. Ensuring adequate copper area around the LED pads helps dissipate heat, maintaining a lower junction temperature and preserving luminous output over time. Avoid placing the LED near other significant heat sources on the board.

7.3 Optical Integration

The right-angle housing directs light parallel to the PCB surface. Designers must consider the height of surrounding components to avoid blocking the viewing angle. The black housing improves contrast, but the surrounding panel or bezel design will also affect the final visual appearance and readability of the indicator.

8. Technical Comparison & Differentiation

Compared to a standard LED package soldered directly to a board, the CBI (Circuit Board Indicator) system offers distinct advantages. The separate housing provides mechanical protection for the LED element and allows for easier replacement or customization of the indicator assembly. The right-angle design saves vertical space (Z-height) on the PCB, which is crucial in slim devices. The stackable feature of the housing enables the creation of dense, multi-indicator arrays (e.g., bar graphs) using a single, simple mechanical design. The use of a white diffused lens over a blue chip produces a softer, more evenly illuminated spot compared to the harsh point source of a clear-lens blue LED, improving viewing comfort and aesthetics.

9. Frequently Asked Questions (FAQ)

Q: Can I drive this LED directly from a 5V logic output or microcontroller pin?

A: No. You must use a series current-limiting resistor. A typical 5V microcontroller pin might source 20-25mA, but without a resistor, the LED's low dynamic resistance would try to draw excessive current, potentially damaging both the LED and the microcontroller pin. Calculate the resistor value based on your supply voltage, the LED's forward voltage (~3.8V), and your desired current (e.g., 10mA).

Q: Why is the storage and handling so strict after opening the bag?

A: The plastic packaging of SMT LEDs can absorb moisture from the air. During the high-temperature reflow soldering process, this trapped moisture rapidly turns to steam, causing internal delamination, cracking, or "popcorning" that destroys the component. The 168-hour floor life and baking procedures are industry-standard methods to manage this Moisture Sensitivity Level (MSL).

Q: The luminous intensity has a wide range (8.7 to 40 mcd). How do I ensure consistent brightness in my product?

A: Specify and purchase LEDs from a single intensity bin. The manufacturer marks a classification code on the packing bag for this purpose. Work with your distributor or supplier to request material from a specific bin that meets your brightness requirements.

Q: Can I use this for reverse voltage protection or as a rectifier?

A: Absolutely not. The datasheet clearly states the device is not designed for reverse operation. The reverse current test (I_R) is for characterization only. Applying a reverse voltage, especially above 5V, will likely cause immediate and irreversible damage to the LED.

10. Design and Usage Case Study

Scenario: Designing a Status Indicator Panel for an Industrial Router

A designer needs multiple status LEDs (Power, LAN Activity, WAN Link, System Error) on the front panel of a compact router. Space on the main PCB is limited. Using the LTL-M11TB1H310Q CBI is an ideal solution. The right-angle housing allows the LEDs to be mounted on the main board, with their light output directed 90 degrees towards a light pipe or window on the router's front bezel. This saves the cost and assembly complexity of a separate indicator PCB. The designer creates a footprint for the CBI housing. They connect each LED in a "Circuit A" configuration: a 5V supply rail, a 120Ω series resistor (calculated for ~10mA at ~3.8V_F), and the LED, all controlled by a GPIO pin on the main processor. They specify to their manufacturer that all LEDs must be from the same luminous intensity bin (e.g., a mid-range bin) to ensure uniform brightness. The assembly instructions mandate that the reel of LEDs, once opened, must be used within 7 days or baked before the reflow process.

11. Operational Principle

The LTL-M11TB1H310Q operates on the principle of electroluminescence in a semiconductor p-n junction. The active region uses an InGaN (Indium Gallium Nitride) compound. When a forward voltage exceeding the diode's turn-on threshold (~3.1-3.8V) is applied, electrons from the n-type region and holes from the p-type region are injected into the active region. When these charge carriers recombine, they release energy in the form of photons (light). The specific composition of the InGaN alloy determines the bandgap energy, which directly corresponds to the wavelength of the emitted light—in this case, blue (~468 nm). This blue light then passes through a phosphor-less white diffused lens. The lens material contains scattering particles that diffuse the light, broadening the emission pattern from a narrow beam to the specified 40° viewing angle and creating a softer, more uniform visual appearance.

12. Technology Trends

Indicator LEDs like the LTL-M11TB1H310Q represent a mature, highly optimized segment of optoelectronics. Ongoing trends focus on further miniaturization while maintaining or increasing light output, enabling even denser indicator arrays. There is a continuous drive for higher efficiency (more mcd per mA) to reduce power consumption in battery-powered devices. Integration is another trend, with some indicators incorporating the current-limiting resistor or even a simple IC driver within the housing to simplify circuit design. The push for broader environmental compliance continues beyond RoHS, addressing substances like REACH SVHCs. Manufacturing processes are also being refined to tighten parameter distributions (like V_F and I_V binning), reducing waste and improving consistency for automated high-volume production.