1. Product Overview
The LTL-M11KS1AH310Q 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 serve as a status or power indicator on printed circuit boards (PCBs). Its design emphasizes ease of assembly and integration into automated SMT production lines.
1.1 Core Advantages
- SMT Compatibility: Designed for standard surface mount assembly processes, enabling high-volume, automated PCB population.
- Enhanced Contrast: The black housing material provides a high contrast ratio against the illuminated LED, improving visibility.
- Design Flexibility: The right-angle form factor allows for light emission parallel to the PCB plane, ideal for side-view applications or space-constrained designs.
- Eco-Friendly: The product is lead-free and compliant with the Restriction of Hazardous Substances (RoHS) directive.
- Reliability: The device undergoes preconditioning accelerated to JEDEC Level 3, indicating a focus on moisture sensitivity and reliability for surface mount components.
1.2 Target Applications
This indicator is suitable for a broad range of electronic equipment where reliable, low-power status indication is required. Typical application sectors include:
- Computer peripherals and motherboards
- Communication equipment (routers, switches, modems)
- Consumer electronics (audio/video equipment, home appliances)
- Industrial control systems and instrumentation
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 at or near these limits is not recommended.
- Power Dissipation (Pd): 72 mW maximum. This is the total power the device can dissipate as heat.
- DC Forward Current (IF): 30 mA maximum continuous current.
- Peak Forward Current: 80 mA, permissible only under pulsed conditions (duty cycle ≤ 1/10, pulse width ≤ 0.1ms).
- Operating Temperature Range (Topr): -40°C to +85°C. The device is rated for industrial temperature environments.
- Storage Temperature Range (Tstg): -40°C to +100°C.
- Lead Soldering Temperature: 260°C for a maximum of 5 seconds, measured 2.0mm from the body. This is critical for wave or hand soldering processes.
2.2 Electrical & Optical Characteristics
These are the typical performance parameters measured at an ambient temperature (TA) of 25°C and a forward current (IF) of 10mA, unless otherwise specified.
- Luminous Intensity (Iv): Ranges from 8.7 mcd (minimum) to 50 mcd (maximum), with a typical value of 25 mcd. The intensity is measured using a filter approximating the photopic (human eye) response curve (CIE). The specific Iv classification code is marked on the product 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. It defines the beam spread of the LED.
- Peak Emission Wavelength (λP): 592 nm. This is the wavelength at which the spectral power output is highest.
- Dominant Wavelength (λd): Ranges from 582 nm to 595 nm, with a typical value of 589 nm. This is the single wavelength perceived by the human eye that defines the color (yellow, in this case), derived from the CIE chromaticity diagram.
- Spectral Line Half-Width (Δλ): 15 nm. This indicates the spectral purity or bandwidth of the emitted light.
- Forward Voltage (VF): Ranges from 2.0V to 2.5V, with a typical value of 2.5V at IF=10mA.
- Reverse Current (IR): 10 μA maximum when a reverse voltage (VR) of 5V is applied. Important: This LED is not designed for operation under reverse bias; this parameter is for test purposes only.
3. Performance Curve Analysis
The datasheet references typical characteristic curves which are essential for design engineers. While the specific graphs are not reproduced in text, their implications are analyzed below.
3.1 Forward Current vs. Forward Voltage (I-V Curve)
This curve would show the non-linear relationship between the current through the LED and the voltage across it. The typical VF of 2.5V at 10mA is a key operating point. Designers use this curve to calculate the necessary current-limiting resistor value for a given supply voltage.
3.2 Luminous Intensity vs. Forward Current
This relationship is generally linear within the operating range. Increasing the forward current increases the light output, but also increases power dissipation and junction temperature, which can affect longevity and color shift.
3.3 Spectral Distribution
The referenced spectral graph would show the relative power output across wavelengths, peaking at 592 nm (λP) with a defined half-width of 15 nm (Δλ), confirming the monochromatic yellow emission.
4. Mechanical & Packaging Information
4.1 Outline Dimensions and Construction
The device features a right-angle black plastic housing. Key mechanical notes include:
- All dimensions are provided in millimeters, with tolerances typically ±0.25mm unless specified otherwise.
- The housing material is black plastic.
- The integrated LED emits yellow light through a white diffused lens, which helps in broadening the viewing angle and softening the light point.
4.2 Polarity Identification
For SMT components, polarity is typically indicated by a marking on the housing or by an asymmetric pad design on the PCB footprint. The datasheet's outline drawing would specify the cathode/anode identification.
4.3 Packing Specification
The product is supplied in tape-and-reel packaging suitable for automated pick-and-place machines.
- Carrier Tape: Made of black conductive polystyrene alloy, 0.40mm thick.
- Reel Capacity: 1,400 pieces per standard 13-inch reel.
- Carton Packaging: Reels are packed with desiccant and a humidity indicator card in Moisture Barrier Bags (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).
5. Soldering & Assembly Guidelines
5.1 Storage Conditions
- Sealed Package: Store at ≤30°C and ≤70% RH. Use within one year.
- Opened Package: Store at ≤30°C and ≤60% RH. Components should be IR-reflow soldered within 168 hours (1 week) of exposure. If stored longer, a 48-hour bake at 60°C is required before soldering to remove absorbed moisture and prevent \"popcorning\" during reflow.
5.2 Soldering Process Parameters
Hand/Wave Soldering: Maximum soldering iron temperature 350°C for ≤3 seconds. For wave soldering, maintain a minimum 2mm clearance from the lens/holder to the solder point. The maximum lead soldering temperature is 260°C for 5 seconds.
Reflow Soldering: The process must comply with a JEDEC-standard temperature profile. Key parameters include:
- Pre-heat: 150-200°C for up to 120 seconds.
- Peak Reflow Temperature: Maximum 260°C.
- Time Above Liquidus: Maximum 5 seconds.
- Critical: The total number of reflow cycles must not exceed two.
The profile must be characterized for the specific PCB design, solder paste, and oven used.
5.3 Cleaning & Handling
- Use alcohol-based solvents like isopropyl alcohol for cleaning if necessary.
- Avoid any mechanical stress on the leads or lens during handling and assembly.
6. Application & Design Considerations
6.1 Drive Circuit Design
LEDs are current-driven devices. To ensure uniform brightness and prevent current hogging, a series current-limiting resistor is mandatory for each LED, even when multiple LEDs are connected in parallel to the same voltage source (see recommended Circuit A in the datasheet). Connecting LEDs directly in parallel without individual resistors (Circuit B) is not recommended, as slight variations in forward voltage (VF) can cause significant differences in current and thus brightness between devices.
The resistor value (R) is calculated using Ohm's Law: R = (V_supply - VF_LED) / I_desired. Using the typical VF of 2.5V and a desired current of 10mA with a 5V supply: R = (5V - 2.5V) / 0.01A = 250 Ohms. A standard 240 or 270 Ohm resistor would be suitable, and its power rating should be checked (P = I²R).
6.2 Thermal Management
While the power dissipation is low (72mW max), ensuring the device operates within its temperature ratings is crucial for long-term reliability. Adequate PCB copper area around the pads can help dissipate heat. Avoid operating at the absolute maximum current (30mA) continuously unless thermal analysis confirms it is safe.
6.3 Optical Integration
The right-angle design directs light horizontally across the PCB. Consider the placement relative to bezels, light pipes, or display panels. The white diffused lens provides a softer, wider light point compared to a clear lens.
7. Technical Comparison & Differentiation
The key differentiating factors of this SMT CBI are its specific combination of attributes: the right-angle black housing, the yellow AlInGaP chip technology (known for high efficiency and stability), the integrated white diffused lens for viewing angle and appearance, and its qualification for standard SMT reflow processes including JEDEC Level 3 preconditioning. This makes it a robust choice for automated manufacturing of professional and industrial electronics where reliability and consistent performance are critical.
8. Frequently Asked Questions (Based on Technical Parameters)
8.1 What is the purpose of the \"Iv classification code\" on the bag?
The luminous intensity (Iv) of LEDs can vary from batch to batch within the min/max specified range. The classification code allows traceability and selection for applications requiring tight brightness matching.
8.2 Can I drive this LED at 20mA instead of 10mA?
Yes, the maximum continuous DC forward current is 30mA. Driving at 20mA will produce higher light output (refer to the Iv vs. IF curve) but will also increase power dissipation (Pd = VF * IF) and junction temperature. Ensure the total Pd does not exceed 72mW and that thermal conditions are acceptable.
8.3 Why is baking required if the bag is opened for more than 168 hours?
SMT plastic packages absorb moisture from the atmosphere. During the high-temperature reflow soldering process, this trapped moisture can vaporize rapidly, creating internal pressure that can delaminate the package or crack the die (\"popcorning\"). Baking drives out this absorbed moisture, making the component safe for reflow.
9. Practical Design Case Study
Scenario: Designing a status indicator panel for an industrial router. Four identical yellow power/activity indicators are needed, spaced along one edge of the PCB, visible from the front panel.
Implementation:
- Component Selection: The LTL-M11KS1AH310Q is chosen for its right-angle emission (light travels to the panel edge), SMT compatibility (automated assembly), and industrial temperature rating.
- PCB Layout: Four identical footprints are placed with the lens facing the board edge. The cathode/anode orientation is consistent. A small amount of copper pour is connected to the thermal pads for heat dissipation.
- Circuit Design: A common 5V rail is used. Each LED has its own 240Ω current-limiting resistor in series, calculated for ~10mA drive current ( (5V - 2.5V)/240Ω ≈ 10.4mA ). This ensures uniform brightness.
- Manufacturing Notes: The assembly house is instructed to follow the JEDEC reflow profile with a peak temperature ≤260°C. The components are kept in sealed bags until just before the SMT line setup to comply with the 168-hour floor life.
10. Operating Principle
The device is a light-emitting diode (LED). When a forward voltage exceeding its characteristic forward voltage (VF) is applied, electrons recombine with holes within the semiconductor material (AlInGaP - Aluminum Indium Gallium Phosphide), releasing energy in the form of photons (light). The specific composition of the semiconductor layers determines the wavelength (color) of the emitted light, which in this case is in the yellow region (~589 nm dominant wavelength). The white diffused epoxy lens encapsulates the chip, providing mechanical protection, shaping the light output (40-degree viewing angle), and diffusing the light source for a softer appearance.
11. Technology Trends
The use of AlInGaP material for yellow LEDs represents mature and highly efficient technology. General trends in indicator LEDs include continued miniaturization, increased luminous efficacy (more light output per watt), broader adoption of high-reliability packaging and testing standards (like JEDEC MSL levels), and integration of features like built-in resistors or IC drivers for simplified circuit design. The focus on RoHS and other environmental compliance standards remains strong across the industry.
LED Specification Terminology
Complete explanation of LED technical terms
Photoelectric Performance
| Term | Unit/Representation | Simple Explanation | Why Important |
|---|---|---|---|
| Luminous Efficacy | lm/W (lumens per watt) | Light output per watt of electricity, higher means more energy efficient. | Directly determines energy efficiency grade and electricity cost. |
| Luminous Flux | lm (lumens) | Total light emitted by source, commonly called "brightness". | Determines if the light is bright enough. |
| Viewing Angle | ° (degrees), e.g., 120° | Angle where light intensity drops to half, determines beam width. | Affects illumination range and uniformity. |
| CCT (Color Temperature) | K (Kelvin), e.g., 2700K/6500K | Warmth/coolness of light, lower values yellowish/warm, higher whitish/cool. | Determines lighting atmosphere and suitable scenarios. |
| CRI / Ra | Unitless, 0–100 | Ability to render object colors accurately, Ra≥80 is good. | Affects color authenticity, used in high-demand places like malls, museums. |
| SDCM | MacAdam ellipse steps, e.g., "5-step" | Color consistency metric, smaller steps mean more consistent color. | Ensures uniform color across same batch of LEDs. |
| Dominant Wavelength | nm (nanometers), e.g., 620nm (red) | Wavelength corresponding to color of colored LEDs. | Determines hue of red, yellow, green monochrome LEDs. |
| Spectral Distribution | Wavelength vs intensity curve | Shows intensity distribution across wavelengths. | Affects color rendering and quality. |
Electrical Parameters
| Term | Symbol | Simple Explanation | Design Considerations |
|---|---|---|---|
| Forward Voltage | Vf | Minimum voltage to turn on LED, like "starting threshold". | Driver voltage must be ≥Vf, voltages add up for series LEDs. |
| Forward Current | If | Current value for normal LED operation. | Usually constant current drive, current determines brightness & lifespan. |
| Max Pulse Current | Ifp | Peak current tolerable for short periods, used for dimming or flashing. | Pulse width & duty cycle must be strictly controlled to avoid damage. |
| Reverse Voltage | Vr | Max reverse voltage LED can withstand, beyond may cause breakdown. | Circuit must prevent reverse connection or voltage spikes. |
| Thermal Resistance | Rth (°C/W) | Resistance to heat transfer from chip to solder, lower is better. | High thermal resistance requires stronger heat dissipation. |
| ESD Immunity | V (HBM), e.g., 1000V | Ability to withstand electrostatic discharge, higher means less vulnerable. | Anti-static measures needed in production, especially for sensitive LEDs. |
Thermal Management & Reliability
| Term | Key Metric | Simple Explanation | Impact |
|---|---|---|---|
| Junction Temperature | Tj (°C) | Actual operating temperature inside LED chip. | Every 10°C reduction may double lifespan; too high causes light decay, color shift. |
| Lumen Depreciation | L70 / L80 (hours) | Time for brightness to drop to 70% or 80% of initial. | Directly defines LED "service life". |
| Lumen Maintenance | % (e.g., 70%) | Percentage of brightness retained after time. | Indicates brightness retention over long-term use. |
| Color Shift | Δu′v′ or MacAdam ellipse | Degree of color change during use. | Affects color consistency in lighting scenes. |
| Thermal Aging | Material degradation | Deterioration due to long-term high temperature. | May cause brightness drop, color change, or open-circuit failure. |
Packaging & Materials
| Term | Common Types | Simple Explanation | Features & Applications |
|---|---|---|---|
| Package Type | EMC, PPA, Ceramic | Housing material protecting chip, providing optical/thermal interface. | EMC: good heat resistance, low cost; Ceramic: better heat dissipation, longer life. |
| Chip Structure | Front, Flip Chip | Chip electrode arrangement. | Flip chip: better heat dissipation, higher efficacy, for high-power. |
| Phosphor Coating | YAG, Silicate, Nitride | Covers blue chip, converts some to yellow/red, mixes to white. | Different phosphors affect efficacy, CCT, and CRI. |
| Lens/Optics | Flat, Microlens, TIR | Optical structure on surface controlling light distribution. | Determines viewing angle and light distribution curve. |
Quality Control & Binning
| Term | Binning Content | Simple Explanation | Purpose |
|---|---|---|---|
| Luminous Flux Bin | Code e.g., 2G, 2H | Grouped by brightness, each group has min/max lumen values. | Ensures uniform brightness in same batch. |
| Voltage Bin | Code e.g., 6W, 6X | Grouped by forward voltage range. | Facilitates driver matching, improves system efficiency. |
| Color Bin | 5-step MacAdam ellipse | Grouped by color coordinates, ensuring tight range. | Guarantees color consistency, avoids uneven color within fixture. |
| CCT Bin | 2700K, 3000K etc. | Grouped by CCT, each has corresponding coordinate range. | Meets different scene CCT requirements. |
Testing & Certification
| Term | Standard/Test | Simple Explanation | Significance |
|---|---|---|---|
| LM-80 | Lumen maintenance test | Long-term lighting at constant temperature, recording brightness decay. | Used to estimate LED life (with TM-21). |
| TM-21 | Life estimation standard | Estimates life under actual conditions based on LM-80 data. | Provides scientific life prediction. |
| IESNA | Illuminating Engineering Society | Covers optical, electrical, thermal test methods. | Industry-recognized test basis. |
| RoHS / REACH | Environmental certification | Ensures no harmful substances (lead, mercury). | Market access requirement internationally. |
| ENERGY STAR / DLC | Energy efficiency certification | Energy efficiency and performance certification for lighting. | Used in government procurement, subsidy programs, enhances competitiveness. |