SMT CBI LED Indicator LTL-M11KS1H310Q Datasheet - Yellow LED with White Diffused Lens - 10mA Forward Current - 2.5V Typical Forward Voltage - English Technical Document

1. Product Overview

The LTL-M11KS1H310Q 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 of this component is to serve as a highly visible status or indicator light on printed circuit boards (PCBs). Its core advantages include ease of assembly due to its SMT compatibility and stackable design for creating arrays, enhanced visual contrast provided by the black housing, and compliance with environmental standards as a lead-free and RoHS-compliant product. The integrated LED features a yellow AlInGaP semiconductor chip encapsulated by a white diffused lens, which broadens the viewing angle and softens the light output. This product is targeted at applications within the computer, communication, consumer electronics, and industrial equipment sectors where reliable, low-power indicator solutions are required.

2. Technical Parameter Analysis

2.1 Absolute Maximum Ratings

The device is specified for operation under the following absolute maximum conditions, measured at an ambient temperature (TA) of 25°C. Exceeding these limits may cause permanent damage.

• Power Dissipation (Pd): 72 mW. This is the maximum power the device can safely dissipate as heat.
• Peak Forward Current (IFP): 80 mA. This current is permissible only under pulsed conditions (duty cycle ≤ 1/10, pulse width ≤ 0.1ms) and must not be used for continuous DC operation.
• DC Forward Current (IF): 30 mA. This is the maximum recommended continuous forward current for reliable long-term operation.
• Operating Temperature Range (Topr): -40°C to +85°C. The device is designed to function within this broad temperature span.
• Storage Temperature Range (Tstg): -40°C to +100°C.
• Lead Soldering Temperature: 260°C for a maximum of 5 seconds, measured 2.0mm (0.079\") from the body of the component. This rating is critical for wave or hand soldering processes.

2.2 Electrical & Optical Characteristics

Key performance parameters are defined at TA=25°C and a standard test current (IF) of 10mA.

• Luminous Intensity (Iv): Ranges from a minimum of 8.7 mcd to a typical value of 25 mcd and a maximum of 50 mcd. The actual Iv value for a specific unit is classified and marked on its packaging.
• Viewing Angle (2θ1/2): 40 degrees. This is the full angle at which the luminous intensity drops to half of its peak (axial) value. The white diffused lens is responsible for achieving this viewing angle.
• Peak Emission Wavelength (λP): 592 nm. This is the wavelength at which the spectral power distribution is at its maximum.
• Dominant Wavelength (λd): Ranges from 582 nm (min) to 589 nm (typ) to 595 nm (max) at IF=10mA. This parameter, derived from the CIE chromaticity diagram, defines the perceived color of the light (yellow).
• Spectral Line Half-Width (Δλ): 15 nm. This indicates the spectral purity or bandwidth of the emitted light.
• Forward Voltage (VF): Typically 2.5V, with a maximum of 2.5V at IF=10mA. The minimum is listed as 2.0V.
• Reverse Current (IR): Maximum 10 μA when a reverse voltage (VR) of 5V is applied. It is explicitly noted that the device is not designed for operation under reverse bias; this test condition is for characterization only.

3. Binning System Explanation

The datasheet indicates the use of a binning system for key optical parameters to ensure consistency in application design. The luminous intensity (Iv) has a classification code that is marked on each individual packing bag. This allows designers to select components from a specific intensity bin to achieve uniform brightness across multiple indicators in a system. Similarly, the dominant wavelength (λd) is specified with min/typ/max values (582/589/595 nm), implying production variation that may be sorted into bins. Designers should consult the specific packing or order information to obtain components from a desired bin for color or intensity matching.

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 detailed in the provided text, standard curves for such a device would typically include:

• Relative Luminous Intensity vs. Forward Current (I-V Curve): Shows how light output increases with current, typically in a sub-linear fashion at higher currents due to heating effects.
• Forward Voltage vs. Forward Current: Illustrates the diode's V-I characteristic, crucial for designing the current-limiting circuitry.
• Relative Luminous Intensity vs. Ambient Temperature: Demonstrates the derating of light output as the junction temperature increases, which is vital for high-temperature environment applications.
• Spectral Distribution: A plot of relative intensity versus wavelength, showing the peak at 592 nm and the 15 nm half-width.

These curves allow engineers to predict performance under their specific operating conditions, such as driving the LED at a current other than 10mA or in an ambient temperature other than 25°C.

5. Mechanical & Package Information

The component is a right-angle SMT package. The holder (housing) is made of black plastic. The key mechanical notes are:

• All dimensions are provided in millimeters with inches in parentheses.
• A general tolerance of ±0.25mm (±0.010\") applies unless otherwise specified on the dimensional drawing.
• The LED itself is yellow, housed within a white diffused lens.
• The physical outline and footprint dimensions are critical for PCB layout to ensure proper fit and soldering. The right-angle design allows the light to be emitted parallel to the PCB surface, which is ideal for edge-lit panels or status indicators viewable from the side of an assembly.

6. Soldering & Assembly Guidelines

6.1 Storage & Handling

The device is moisture-sensitive. In its original sealed Moisture Barrier Bag (MBB) with desiccant, it should be stored at ≤30°C and ≤70% RH and used within one year. Once the bag is opened, the storage environment must not exceed 30°C and 60% RH. Components exposed beyond 168 hours require baking at approximately 60°C for at least 48 hours before soldering to prevent \"popcorning\" damage during reflow.

6.2 Soldering Process

Detailed soldering instructions are provided to prevent thermal or mechanical damage:

• Reflow Soldering: A maximum of two reflow cycles is allowed. A sample temperature profile compliant with JEDEC standards is referenced, typically involving a pre-heat stage (150-200°C for up to 120s) and a peak solder wave temperature not exceeding 260°C for a maximum of 5 seconds.
• Hand/Wave Soldering: When using a soldering iron, the tip temperature should not exceed 350°C, and contact time should be limited to 3 seconds maximum, once only. A minimum clearance of 2mm must be maintained between the solder point and the base of the lens/holder.
• Cleaning: Isopropyl alcohol or similar alcohol-based solvents are recommended if cleaning is necessary.
• Mechanical Stress: During assembly, minimal clinch force should be used to avoid stress on the leads or housing.

7. Packaging & Ordering Information

The packing specification is detailed for automated assembly:

• Carrier Tape: Components are supplied on 13-inch reels. The carrier tape is made of black conductive polystyrene alloy, 0.40mm ±0.06mm thick, with a 10-sprocket-hole pitch cumulative tolerance of ±0.20.
• Reel Capacity: Each 13\" reel contains 1,400 pieces.
• Carton Packing: One reel is packed with a humidity indicator card and desiccant in one Moisture Barrier Bag (MBB). Three MBBs are packed in one Inner Carton (total 4,200 pcs). Ten Inner Cartons are packed in one Outer Carton (total 42,000 pcs).
• Part Number: The base ordering code is LTL-M11KS1H310Q.

8. Application Recommendations

8.1 Typical Application Circuits

LEDs are current-driven devices. To ensure uniform brightness when driving multiple LEDs in parallel, it is strongly recommended to use a individual current-limiting resistor in series with each LED. The datasheet references a \"Circuit Model (A)\" which depicts this configuration: Power Supply (+) -> Resistor -> LED Anode -> LED Cathode -> Power Supply (-). This method compensates for minor variations in the forward voltage (VF) of individual LEDs, preventing current hogging and uneven illumination. The resistor value can be calculated using Ohm's Law: R = (V_supply - VF_LED) / I_desired, where I_desired should not exceed the maximum DC forward current of 30mA.

8.2 Design Considerations

• Thermal Management: While power dissipation is low (72mW max), ensuring adequate PCB copper area or thermal relief around the solder pads can help maintain lower junction temperatures, preserving luminous intensity and longevity.
• Optical Design: The 40-degree viewing angle and white diffused lens provide a wide, soft light emission. For applications requiring a more focused beam, external lenses or light guides may be necessary.
• Polarity: As a diode, correct anode/cathode orientation is essential. The PCB footprint design must clearly indicate polarity to prevent assembly errors.

9. Technical Comparison & Differentiation

The LTL-M11KS1H310Q differentiates itself through its integrated right-angle SMT holder design. Compared to standard chip LEDs that are soldered directly to the board, this CBI package offers mechanical protection for the LED, easier handling for assembly, and a defined optical orientation. The black housing significantly improves the contrast ratio, making the indicator appear brighter and more defined when off, which is a key advantage over clear or white housings. The use of AlInGaP technology for the yellow chip offers high efficiency and stability compared to older technologies.

10. Frequently Asked Questions (FAQ)

10.1 Can I drive this LED without a current-limiting resistor?

Answer: No. Driving an LED directly from a voltage source is not recommended and will likely destroy the device due to overcurrent. An LED's forward voltage has a negative temperature coefficient and can vary from unit to unit. A series resistor (or a constant current driver) is mandatory for stable and safe operation.

10.2 What is the difference between Peak Wavelength and Dominant Wavelength?

Answer: Peak Wavelength (λP) is the single wavelength where the LED emits the most optical power. Dominant Wavelength (λd) is a calculated value from colorimetry that represents the perceived color. For a monochromatic source like this yellow LED, they are often close, but λd is the more relevant parameter for color specification in human-centric applications.

10.3 Why is there a strict time limit for reflow after opening the bag?

Answer: The plastic packaging is hygroscopic (absorbs moisture). During the high-temperature reflow soldering process, this absorbed moisture can rapidly turn to steam, causing internal delamination, cracking, or \"popcorning,\" which permanently damages the device. The 168-hour floor life and baking procedures are designed to remove this moisture.

11. Practical Use Case Example

Scenario: Designing a status indicator panel for a network router. The panel requires multiple yellow LEDs to show link activity and power status, viewable from the front panel. The designer selects the LTL-M11KS1H310Q for its right-angle emission (light shines forward), black housing (high contrast against the bezel), and SMT compatibility (enables automated assembly). On the PCB, the designer creates a footprint matching the component's datasheet dimensions. Each LED is driven in a parallel configuration from a 5V rail. Using the typical VF of 2.5V and a target current of 10mA for adequate brightness, a series resistor of R = (5V - 2.5V) / 0.01A = 250 Ohms is calculated. A standard 240 Ohm or 270 Ohm resistor is selected. The PCB layout maintains the recommended 2mm clearance between the pad and the LED housing. After assembly, the LEDs provide uniform, bright yellow indicators that are easily visible from the intended viewing angle.

12. Operating Principle

The device operates on the principle of electroluminescence in a semiconductor diode. The active region of the LED is composed of Aluminum Indium Gallium Phosphide (AlInGaP). When a forward bias voltage (exceeding the diode's forward voltage, ~2.5V) is applied, electrons from the n-type semiconductor and holes from the p-type semiconductor 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 AlInGaP alloy determines the bandgap energy, which directly corresponds to the wavelength (color) of the emitted light—in this case, yellow (~589 nm). The generated light passes through a white diffused epoxy lens, which scatters the photons to create a wider, more uniform viewing angle.

13. Technology Trends

The component reflects several ongoing trends in optoelectronics: the continued dominance of Surface Mount Technology (SMT) for miniaturization and automated assembly; the use of advanced semiconductor materials like AlInGaP for high-efficiency colored LEDs; and the integration of mechanical and optical elements (the holder and diffused lens) into a single, user-friendly package. Future developments in this product category may focus on further miniaturization, increased luminous efficacy (more light output per watt), broader adoption of chip-scale packaging (CSP), and integration of smart features or drivers into the package. The emphasis on RoHS compliance and lead-free manufacturing is now a standard industry requirement driven by global environmental regulations.