SMT Green LED Indicator LTL-M11TG1H310Q Datasheet - Right-Angle Holder - 525nm Green - 3.8V - 80mW - English Technical Document

1. Product Overview

The LTL-M11TG1H310Q is a Circuit Board Indicator (CBI) component designed for surface-mount assembly. It consists of a green LED lamp integrated into a black plastic right-angle holder (housing). This design is intended for applications requiring side-emitting indicators on printed circuit boards (PCBs). The product is characterized by its stackable design, which facilitates easy assembly and allows for the creation of vertical or horizontal arrays of indicators.

1.1 Core Features and Advantages

• Surface Mount Technology (SMT) Compatible: Designed for automated pick-and-place and reflow soldering processes, enhancing manufacturing efficiency.
• Enhanced Contrast: The black plastic housing provides a high contrast background, improving the visibility and perceived brightness of the illuminated LED.
• High Efficiency: Offers low power consumption while delivering sufficient luminous intensity for indicator purposes.
• Environmental Compliance: This is a lead-free product and is compliant with the RoHS (Restriction of Hazardous Substances) directive.
• Optical Design: Utilizes an InGaN (Indium Gallium Nitride) green semiconductor chip. The light is emitted through a white diffused lens, which helps to scatter the light for a wider, more uniform viewing pattern.
• Reliability: The components undergo preconditioning accelerated to JEDEC Moisture Sensitivity Level 3, indicating a certain level of robustness against moisture-induced damage during soldering.

1.2 Target Applications and Markets

This indicator is suitable for a broad range of electronic equipment where status indication is required. Primary application sectors include:

• Computer Equipment: Power, disk activity, or network status indicators on motherboards, servers, or peripherals.
• Communication Devices: Signal strength, link activity, or mode indicators in routers, switches, and modems.
• Consumer Electronics: Standby, charging, or operational status lights in appliances, audio/video equipment, and home automation devices.
• Industrial Equipment: Machine status, fault indication, or operational mode lights in control panels and instrumentation.

2. Technical Parameter Deep Dive

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 (Pd): 80 mW. This is the maximum amount of power the device can dissipate as heat without damage.
• Peak Forward Current (I_FP): 100 mA. This maximum current is allowed only under pulsed conditions (duty cycle ≤ 10%, pulse width ≤ 0.1ms).
• DC Forward Current (I_F): 20 mA. This is the maximum continuous forward current recommended for reliable operation.
• Operating Temperature Range (T_opr): -40°C to +85°C. The ambient temperature range over which the device is designed to function.
• Storage Temperature Range (T_stg): -40°C to +100°C.
• Soldering Temperature: Withstands 260°C for a maximum of 5 seconds, which is typical for lead-free reflow soldering profiles.

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): 29 millicandelas (mcd) minimum at a forward current (I_F) of 10 mA. This quantifies the perceived brightness as measured by a sensor filtered to match the human eye's photopic response.
• Viewing Angle (2θ_1/2): 40 degrees. This is the full angle at which the luminous intensity drops to half of its value measured on the central axis. A 40-degree angle indicates a moderately focused beam.
• Peak Emission Wavelength (λ_P): 523 nanometers (nm). This is the wavelength at which the spectral power output is highest.
• Dominant Wavelength (λ_d): Ranges from 518 nm to 536 nm, with a typical value of 525 nm. This is the single wavelength perceived by the human eye that defines the color of the light, derived from the CIE chromaticity diagram.
• Spectral Line Half-Width (Δλ): 25 nm. This indicates the spectral purity; a smaller value means a more monochromatic light. 25 nm is typical for a standard green LED.
• Forward Voltage (V_F): Typically 3.8V, with a maximum of 3.8V at I_F = 10 mA. This is the voltage drop across the LED when operating.
• Reverse Current (I_R): 10 μA maximum when a reverse voltage (V_R) of 5V is applied. Important: The device is not designed for reverse-bias operation; this parameter is for leakage current testing only.

3. Performance Curve Analysis

The datasheet references typical characteristic curves which are essential for circuit design. 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 shows the exponential relationship between current and voltage for a semiconductor diode. For designers, the key takeaway is the typical V_F of 3.8V at 10mA. This curve is crucial for selecting an appropriate current-limiting resistor. The voltage increases non-linearly with current; operating significantly above 20mA will cause V_F to rise sharply, leading to excessive power dissipation and potential damage.

3.2 Luminous Intensity vs. Forward Current

This graph typically shows that light output (I_V) increases approximately linearly with forward current (I_F) within the recommended operating range. However, efficiency (light output per unit of electrical power) may decrease at very high currents due to increased heat generation. Operating at the typical 10mA provides a good balance of brightness and efficiency.

3.3 Luminous Intensity vs. Ambient Temperature

The light output of an LED decreases as the junction temperature increases. This curve is vital for applications operating in high-temperature environments. A designer must derate the expected luminous intensity if the device will be used near its maximum operating temperature of 85°C.

3.4 Spectral Distribution

The referenced spectral graph would show a bell-shaped curve centered around the peak wavelength of 523 nm with a half-width of 25 nm. This confirms the green color emission.

4. Mechanical and Packaging Information

4.1 Outline Dimensions and Notes

The mechanical drawing provides critical dimensions for PCB footprint design and clearance checks. Key notes from the datasheet include:

• All dimensions are in millimeters (with inch equivalents).
• A general tolerance of ±0.25mm (±0.010\") applies unless a specific tolerance is stated.
• The holder/housing material is black plastic.
• The integrated LED emits green light (525nm dominant wavelength) through a white diffused lens.

Designer Note: Always refer to the latest dimensional drawing from the manufacturer for PCB layout. The right-angle design means the light emits parallel to the PCB surface, which is ideal for panel-mounted applications.

4.2 Polarity Identification

For surface-mount devices, polarity is typically indicated by a marking on the component body or an asymmetrical shape. The designer must consult the footprint diagram to identify the cathode and anode pads on the PCB layout to ensure correct orientation during assembly.

5. Soldering and Assembly Guidelines

5.1 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 the moisture barrier bag, the storage environment must not exceed 30°C and 60% RH.
• Floor Life: It is recommended to complete the IR reflow process within 168 hours (7 days) after opening the original packaging.
• Extended Storage/Baking: If exposure exceeds 168 hours, the components must be baked at approximately 60°C for at least 48 hours before soldering to remove absorbed moisture and prevent \"popcorning\" during reflow.

5.2 Cleaning

If cleaning is necessary after soldering, use alcohol-based solvents like isopropyl alcohol. Avoid using aggressive or unknown chemical cleaners that may damage the plastic housing or lens.

5.3 Soldering Process Parameters

Reflow Soldering (Recommended Process):

• Pre-heat: 150–200°C for up to 120 seconds maximum.
• Peak Temperature: 260°C maximum at the component leads.
• Time Above Liquidus (TAL): 5 seconds maximum (for lead-free solder).
• Number of Cycles: The reflow process must not be performed more than two times.

Hand Soldering (if necessary):

• Iron Temperature: 300°C maximum.
• Contact Time: 3 seconds maximum per solder joint.

Critical Caution: Do not apply any mechanical stress to the leads or housing while the LED is at high temperature during soldering, as this can cause internal damage.

6. Packaging and Ordering Information

6.1 Tape and Reel Specifications

• Carrier Tape: Made of black conductive polystyrene alloy, 0.40mm thick.
• Reel Size: Standard 13-inch (330mm) diameter reel.
• Quantity per Reel: 1,400 pieces.

6.2 Carton Packaging

• Each reel is packaged with a desiccant and a humidity indicator card inside a Moisture Barrier Bag (MBB).
• Three MBBs are packed into one inner carton (total 4,200 pieces).
• Ten inner cartons are packed into one outer shipping carton (total 42,000 pieces).

7. Application Design and Circuit Considerations

7.1 Drive Circuit Design

LEDs are current-driven devices. To ensure consistent brightness and longevity, they must be driven with a constant current or a voltage source with a series current-limiting resistor.

Recommended Circuit (Circuit A): Use a series resistor for each LED. The resistor value (R) is calculated using Ohm's Law: R = (V_supply - V_F) / I_F. For a 5V supply, targeting I_F=10mA and using V_F=3.8V: R = (5V - 3.8V) / 0.01A = 120 Ω. A standard 120Ω resistor would be suitable.

Circuit to Avoid (Circuit B): Connecting multiple LEDs directly in parallel from a single voltage source with one shared current-limiting resistor is not recommended. Small variations in the forward voltage (V_F) characteristic between individual LEDs will cause uneven current distribution, leading to significant differences in brightness and potentially overstressing one LED.

7.2 Electrostatic Discharge (ESD) Protection

LEDs are sensitive to electrostatic discharge. Standard ESD precautions must be observed during handling and assembly:

• Use grounded workstations and wrist straps.
• Store and transport components in ESD-safe packaging.
• Avoid touching the component leads directly.

7.3 Thermal Management

While the power dissipation is low (80mW max), proper thermal design extends lifetime and maintains light output. Ensure adequate spacing between components on the PCB for airflow. Avoid placing the LED near other significant heat sources. Operating at or below the typical current (10mA) rather than the absolute maximum (20mA) will minimize temperature rise.

8. Frequently Asked Questions (FAQ)

8.1 What is the purpose of the white diffused lens?

The white diffused lens scatters the light from the small, bright green chip. This creates a more uniform, wider viewing angle (40 degrees) and softens the appearance of the light source, making it look like a solid illuminated area rather than a pinpoint, which is generally more desirable for status indicators.

8.2 Can I drive this LED with a 3.3V supply?

Possibly, but with caution. The typical forward voltage is 3.8V. At 3.3V, the LED may not turn on at all, or it will be very dim because the applied voltage is below the required V_F threshold. A boost converter or a higher supply voltage (like 5V) with a series resistor is the recommended approach.

8.3 How do I interpret the luminous intensity value of 29 mcd?

Millicandela (mcd) is a unit of luminous intensity, which is a measure of how bright a light source appears in a specific direction. 29 mcd is a moderate brightness suitable for direct viewing in typical indoor electronic equipment. For comparison, a power indicator on a laptop might be in the range of 20-100 mcd.

8.4 Is the housing material conductive?

The carrier tape is specified as \"black conductive polystyrene alloy,\" which is for anti-static purposes during automated handling. The device housing itself is standard black plastic and is not electrically conductive.