LTL-R42M12NH51 Through Hole LED Lamp Datasheet - Multi-Color - 20mA - English Technical Document

1. Product Overview

The LTL-R42M12NH51 is a multi-color Circuit Board Indicator (CBI) designed for through-hole mounting on printed circuit boards (PCBs). It features a black plastic right-angle housing that mates with integrated LED lamps. This component is engineered for ease of assembly and provides a high-contrast visual indicator suitable for various electronic applications.

1.1 Core Advantages

• Ease of Assembly: The design facilitates straightforward circuit board assembly processes.
• Enhanced Contrast: The black housing material improves the contrast ratio, making the LED light more visible.
• Energy Efficiency: Features low power consumption and high luminous efficiency.
• Environmental Compliance: This is a lead-free product compliant with RoHS (Restriction of Hazardous Substances) directives.
• Versatile Packaging: The CBI concept supports various configurations, including top-view or right-angle orientations and stackable horizontal or vertical arrays.

1.2 Target Applications

This LED lamp is suitable for a broad range of electronic equipment, including:

• Computer systems and peripherals
• Communication devices
• Consumer electronics
• Industrial equipment and controls

2. Technical Parameter Deep-Dive

This section provides a detailed, objective analysis of the key electrical, optical, and thermal parameters specified for the LTL-R42M12NH51 LED lamp.

2.1 Absolute Maximum Ratings

These ratings define the stress limits beyond which permanent damage to the device may occur. Operation at or beyond these limits is not advised.

• Power Dissipation (Pd): 52 mW for Red, Yellow, and Yellow Green LEDs; 117 mW for the Blue LED. This parameter indicates the maximum power the LED can dissipate as heat at an ambient temperature (TA) of 25°C.
• Peak Forward Current (I_FP): 60 mA for Red/Yellow/Yellow Green; 100 mA for Blue. This is the maximum allowable pulsed current (duty cycle ≤ 1/10, pulse width ≤ 0.1ms).
• DC Forward Current (I_F): 20 mA for all colors. This is the recommended continuous operating current.
• Temperature Ranges: Operating: -40°C to +85°C; Storage: -40°C to +100°C. These define the environmental limits for reliable function and non-operational storage.
• Lead Soldering Temperature: 260°C maximum for 5 seconds, measured 2.0mm from the LED body. This is critical for wave or hand soldering processes.

2.2 Electrical & Optical Characteristics

Measured at TA=25°C under standard test conditions. The device contains four LEDs: LED1 (Red/Yellow Bicolor), LED2 & LED3 (Yellow Green), and LED4 (Blue).

• Luminous Intensity (I_V):
  • Red/Yellow (LED1 @ 20mA): Typical 110 mcd, ranging from 50 mcd (Min) to 240 mcd (Max).
  • Yellow Green (LED2,3 @ 10mA): Typical 19 mcd, ranging from 8.7 mcd to 50 mcd.
  • Blue (LED4 @ 20mA): Typical 400 mcd, ranging from 180 mcd to 880 mcd.
  • Note: Guaranteed I_V includes a ±30% testing tolerance.
• Viewing Angle (2θ_1/2): 100 degrees for Red, Yellow, and Yellow Green; 60 degrees for Blue. This is the total angle where intensity is at least half the peak axial intensity.
• Wavelength:
  • Peak Emission (λ_P): Red ~632 nm, Yellow ~591 nm, Yellow Green ~572 nm, Blue ~468 nm.
  • Dominant Wavelength (λ_d): Defines the perceived color. Ranges: Red 617-632 nm, Yellow 583-596 nm, Yellow Green 566-574 nm, Blue 460-475 nm.
• Spectral Line Half-Width (Δλ): ~20 nm for Red/Yellow/Blue; ~15 nm for Yellow Green. This indicates the color purity.
• Forward Voltage (V_F):
  • Red: Typical 2.1V (Max 2.6V)
  • Yellow: Typical 2.1V (Max 2.6V)
  • Yellow Green: Typical 2.0V (Max 2.6V)
  • Blue: Typical 3.2V (Max 3.8V)
• Reverse Current (I_R): 100 μA maximum at a reverse voltage (V_R) of 5V. Critical Note: The device is not designed for reverse operation; this test condition is for characterization only.

2.3 Thermal Characteristics

The primary thermal consideration is the power dissipation limit (Pd), which decreases as ambient temperature increases. The specified Pd values are valid at 25°C. For reliable long-term operation, maintaining junction temperature within limits by managing ambient temperature and PCB thermal design is essential. The wide operating temperature range (-40°C to +85°C) indicates robustness for various environments.

3. Binning System Explanation

The datasheet implies performance variations through Min/Typ/Max specifications. Key parameters subject to binning or natural variation include:

• Luminous Intensity (I_V) Binning: As shown, I_V has a wide range (e.g., Blue: 180-880 mcd). Designers must account for this ±30% testing tolerance range to ensure consistent brightness in their application, potentially by using current-limiting resistors or selecting binned parts.
• Wavelength/Dominant Wavelength Binning: The specified ranges for λ_d (e.g., Red: 617-632 nm) define the possible color variation. Applications requiring precise color matching may need parts binned to tighter wavelength tolerances.
• Forward Voltage (V_F) Binning: The V_F ranges (e.g., Blue: 3.2V Typ, 3.8V Max) are important for designing the driving circuit, especially when multiple LEDs are connected in parallel, to ensure uniform current distribution.

4. Performance Curve Analysis

The datasheet references typical characteristic curves. While the specific graphs are not reproduced in the text, they typically include the following relationships, crucial for design:

• I-V (Current-Voltage) Curve: Shows the relationship between forward voltage (V_F) and forward current (I_F). It is non-linear, resembling a diode curve with a turn-on voltage specific to the semiconductor material (lower for Red/Yellow/Green, higher for Blue).
• Relative Luminous Intensity vs. Forward Current: Demonstrates how light output increases with current, typically in a near-linear relationship within the operating range, before efficiency drops at very high currents.
• Relative Luminous Intensity vs. Ambient Temperature: Shows the derating of light output as the junction temperature increases. This is critical for applications operating at high ambient temperatures.
• Spectral Distribution: A graph of relative intensity vs. wavelength, showing the peak emission wavelength (λ_P) and the spectral half-width (Δλ).

5. Mechanical & Package Information

5.1 Outline Dimensions

The device uses a right-angle through-hole package. Key dimensional notes:

• All dimensions are in millimeters, with a default tolerance of ±0.25mm unless otherwise specified.
• The housing material is black plastic.
• The specific lens configuration is: LED1 (Red/Yellow bicolor) has a white diffused lens; LED2 & LED3 (Yellow Green) have green diffused lenses; LED4 (Blue) has a white diffused lens.

5.2 Polarity Identification

Polarity must be observed during assembly. The datasheet's outline drawing would typically indicate the cathode (negative) lead, often by a flat spot on the lens housing, a shorter lead, or a specific marking on the PCB footprint diagram. Correct polarity is essential for device operation.

6. Soldering & Assembly Guidelines

Proper handling is critical to prevent damage.

• Storage: Store at ≤30°C and ≤70% relative humidity. Use within 3 months if removed from original packaging. For longer storage, use a sealed container with desiccant or a nitrogen ambient.
• Cleaning: Use alcohol-based solvents like isopropyl alcohol if necessary.
• Lead Forming: Bend leads at a point ≥3mm from the base of the LED lens. Perform forming before soldering at room temperature. Avoid using the lead frame base as a fulcrum.
• PCB Assembly: Apply minimum clinch force to avoid mechanical stress.
• Soldering:
  • Maintain a minimum 2mm clearance from the lens/holder base to the solder point.
  • Avoid immersing the lens/holder in solder.
  • Avoid external stress on leads during soldering while the LED is hot.
  • Recommended Conditions:
    • Soldering Iron: 350°C max, 3 seconds max per joint.
    • Wave Soldering: Pre-heat ≤120°C for ≤100s; Solder wave ≤260°C for ≤5s.
  • Warning: Excessive temperature or time can deform the lens or cause catastrophic failure.

7. Drive Method & Circuit Design

LEDs are current-operated devices.

• Recommended Circuit (Circuit A): Use a current-limiting resistor in series with each LED when connecting multiple LEDs in parallel. This ensures uniform brightness by compensating for variations in the forward voltage (V_F) of individual LEDs.
• Non-Recommended Circuit (Circuit B): Connecting multiple LEDs in parallel with a single shared current-limiting resistor is discouraged. Small differences in I-V characteristics will cause uneven current distribution, leading to significant differences in brightness between LEDs.
• The drive current should not exceed the specified DC Forward Current (20mA for all colors).

8. Electrostatic Discharge (ESD) Protection

LEDs are susceptible to damage from static electricity.

• Prevention Measures:
  • Use conductive wrist straps or anti-static gloves.
  • Ensure all equipment, workstations, and storage racks are properly grounded.
  • Use ionizers to neutralize static charge on plastic lenses.
• ESD Training: Personnel working in static-safe areas should be ESD-certified.

9. Packaging Specification

The datasheet includes a dedicated section (6) for packing specifications. This typically details:

• The carrier medium (e.g., tape and reel, tube, bulk).
• Quantities per reel/tube.
• Reel dimensions and orientation.
• Labeling information for traceability.

10. Application Notes & Design Considerations

10.1 Typical Application Scenarios

Ideal for status indicators, power-on lights, mode indicators, and backlighting in the target markets (Computer, Communication, Consumer, Industrial). The right-angle form factor is particularly useful when the PCB is mounted perpendicular to the user's line of sight.

10.2 Design Considerations

• Current Limiting: Always use a series resistor. Calculate resistor value using R = (V_supply - V_F) / I_F. Use the maximum V_F from the datasheet to ensure I_F does not exceed 20mA under worst-case conditions.
• Thermal Management: Consider PCB layout for heat dissipation, especially if operating at high ambient temperatures or near maximum current.
• Visual Design: The black housing improves contrast, but the viewing angle differs between colors (wider for Red/Yellow/Green, narrower for Blue). Account for this in the mechanical design of bezels or light pipes.

11. Frequently Asked Questions (Based on Technical Parameters)

• Q: Can I drive the Blue LED at the same 20mA as the others?
  
  A: Yes, the DC Forward Current for all colors, including Blue, is specified as 20mA.
• Q: Why is the forward voltage for the Blue LED higher?
  
  A: Blue LEDs are typically made from InGaN (Indium Gallium Nitride) semiconductor material, which has a wider bandgap than the materials used for Red/Yellow/Green LEDs (like AlInGaP). A wider bandgap requires a higher voltage to energize electrons and produce photons.
• Q: What happens if I connect the LED in reverse polarity?
  
  A: Applying a reverse voltage can cause a high reverse current (up to 100 μA at 5V per the test condition) and likely damage the LED. The device is not designed for reverse operation. Always observe polarity.
• Q: How do I ensure uniform brightness in a multi-LED design?
  
  A: Use the recommended Circuit A: a separate current-limiting resistor for each LED. Do not connect multiple LEDs in parallel to a single resistor (Circuit B).

12. Operational Principles

Light Emitting Diodes (LEDs) are semiconductor devices that emit light through electroluminescence. When a forward voltage is applied across the p-n junction, electrons and holes recombine, releasing energy in the form of photons. The color (wavelength) of the emitted light is determined by the bandgap energy of the semiconductor material used. The LTL-R42M12NH51 integrates multiple semiconductor chips within a single housing to produce different colors (Red/Yellow/Yellow Green/Blue). The diffused lens material helps scatter the light, creating a wider and more uniform viewing pattern.