LTL2R3TBM3K LED Lamp Datasheet - T-1 3/4 Package - 3.0V Max - 90mW - Blue/White - English Technical Document

1. Product Overview

This document details the specifications for a through-hole white LED lamp, identified by part number LTL2R3TBM3K. The device is designed for status indication and general illumination across a broad range of electronic applications. It features a popular T-1 3/4 (approximately 5mm) diameter package with a water-clear lens, housing an InGaN (Indium Gallium Nitride) blue chip which, combined with a phosphor coating, produces white light.

The core advantages of this component include its compliance with RoHS directives, indicating it is lead-free. It offers low power consumption paired with high efficiency, making it suitable for energy-conscious designs. Its through-hole design allows for versatile mounting on printed circuit boards (PCBs) or panels, and it is compatible with integrated circuit logic levels due to its low current requirements.

The target markets for this LED are diverse, encompassing computer peripherals, communication equipment, consumer electronics, home appliances, and industrial control systems where reliable, long-lasting indicator lighting is required.

2. Technical Parameter Deep-Dive

2.1 Absolute Maximum Ratings

All ratings are specified at an ambient temperature (TA) of 25°C. Exceeding these limits may cause permanent damage.

• Power Dissipation (Pd): 90 mW maximum. This is the total power the device can safely dissipate as heat.
• Peak Forward Current (IFP): 100 mA maximum. This current can only be applied under pulsed conditions with a duty cycle ≤ 1/10 and a pulse width ≤ 10ms.
• DC Forward Current (IF): 30 mA maximum for continuous operation.
• Current Derating: The maximum DC forward current must be linearly derated by 0.5 mA for every degree Celsius above 40°C ambient temperature.
• Operating Temperature Range: -40°C to +85°C.
• Storage Temperature Range: -40°C to +100°C.
• Lead Soldering Temperature: 260°C for a maximum of 5 seconds, measured 2.0mm (0.079\") from the LED body.

2.2 Electrical & Optical Characteristics

These parameters define the device's performance under standard test conditions (TA=25°C, IF=5mA unless noted).

• Radiant Intensity (Ie): 8.4 to 17.6 mW/sr. This measures the optical power emitted per unit solid angle. The specific value is binned (see Section 4). The guarantee includes a ±15% testing tolerance.
• Viewing Angle (2θ1/2): 30 degrees (typical). This is the full angle at which the radiant intensity drops to half of its value on the central axis.
• Peak Emission Wavelength (λP): 464 to 472 nm. This indicates the dominant blue wavelength emitted by the chip before phosphor conversion to white light.
• Spectral Line Half-Width (Δλ): 25 nm (typical). This specifies the width of the primary blue emission peak at half its maximum intensity.
• Forward Voltage (VF): 2.6 to 3.0 V at 5mA. This is binned (see Section 4).
• Reverse Current (IR): 10 μA maximum at a reverse voltage (VR) of 5V. Important: The device is not designed for operation under reverse bias; this test condition is for leakage characterization only.

3. Bin Table Specification

The LEDs are sorted into bins based on key performance parameters to ensure consistency within a production lot. The bin code is marked on each packing bag.

3.1 Radiant Intensity (Ie) Binning

Measured at IF = 5mA. Tolerance for each bin limit is ±15%.

• Bin A: 8.4 – 10.2 mW/sr
• Bin B: 10.2 – 12.2 mW/sr
• Bin C: 12.2 – 14.7 mW/sr
• Bin D: 14.7 – 17.6 mW/sr

3.2 Forward Voltage (VF) Binning

Measured at IF = 5mA. Tolerance for each bin limit is ±0.1V.

• Bin 1: 2.60 – 2.80 V
• Bin 2: 2.80 – 3.00 V

4. Performance Curve Analysis

The datasheet references typical characteristic curves which graphically represent device behavior. While the specific graphs are not reproduced in text, they typically include:

• Relative Radiant Intensity vs. Forward Current: Shows how light output increases with current, usually in a near-linear relationship within the operating range.
• Forward Voltage vs. Forward Current: The IV curve, demonstrating the exponential relationship typical of a diode.
• Relative Radiant Intensity vs. Ambient Temperature: Illustrates the decrease in light output as junction temperature rises, a critical factor for thermal management.
• Spectral Distribution: A plot of relative intensity versus wavelength, showing the primary blue peak and the broader phosphor-converted spectrum that combines to create white light.

These curves are essential for designers to predict performance under non-standard conditions and to optimize drive circuits.

5. Mechanical & Package Information

5.1 Outline Dimensions

The device uses a standard T-1 3/4 radial leaded package. Key dimensional notes include:

• All dimensions are in millimeters (inches provided in parentheses).
• Standard tolerance is ±0.25mm (0.010\") unless otherwise specified.
• The maximum protrusion of resin under the flange is 1.0mm (0.04\").
• Lead spacing is measured at the point where the leads exit the package body.

The physical design allows for easy insertion into standard PCB holes and provides mechanical stability after soldering.

6. Soldering & Assembly Guidelines

6.1 Storage

For optimal shelf life, LEDs should be stored in an environment not exceeding 30°C and 70% relative humidity. If removed from the original moisture-barrier bag, they should be used within three months. For longer-term storage outside the original packaging, use a sealed container with desiccant or a nitrogen-filled desiccator.

6.2 Cleaning

If cleaning is necessary, use only alcohol-based solvents such as isopropyl alcohol. Harsh or abrasive cleaners should be avoided.

6.3 Lead Forming

If leads need to be bent, this must be done before soldering and at room temperature. The bend should be made at least 3mm away from the base of the LED lens. The package body must not be used as a fulcrum during bending. During PCB assembly, apply the minimum clinch force necessary to avoid imposing excessive mechanical stress on the component.

6.4 Soldering Process

A minimum clearance of 2mm must be maintained between the base of the epoxy lens and the solder point. The lens must never be immersed in solder. Avoid applying external stress to the leads while the LED is at elevated temperature.

Recommended Soldering Conditions:

• Soldering Iron: Temperature ≤ 350°C, time ≤ 3 seconds (one time only).
• Wave Soldering: Pre-heat ≤ 100°C for ≤ 60 seconds, solder wave ≤ 260°C for ≤ 5 seconds.

Critical Warning: Excessive soldering temperature or time can deform the lens or cause catastrophic LED failure. Infrared (IR) reflow soldering is not suitable for this through-hole type LED lamp.

7. Packaging & Ordering Information

7.1 Packaging Specification

The LEDs are packed in anti-static bags. Standard packing quantities are:

• Per Bag: 500, 200, or 100 pieces.
• Per Inner Carton: 10 bags, totaling 5,000 pieces.
• Per Outer Carton (Master Case): 8 inner cartons, totaling 40,000 pieces.

Within a shipping lot, only the final pack may contain a non-full quantity.

8. Application Recommendations

8.1 Typical Applications

This LED is suitable for both indoor and outdoor signage, as well as general electronic equipment requiring status indication, backlighting, or general illumination.

8.2 Drive Circuit Design

LEDs are current-operated 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 (Circuit Model A). Driving LEDs in parallel without individual resistors (Circuit Model B) is not recommended, as small variations in the forward voltage (VF) characteristic between individual LEDs will cause significant differences in current sharing and, consequently, uneven brightness.

The series resistor value (R) can be calculated using Ohm's Law: R = (Vcc - VF) / IF, where Vcc is the supply voltage, VF is the LED's forward voltage (use max value from bin for reliability), and IF is the desired forward current.

8.3 Electrostatic Discharge (ESD) Protection

This LED is susceptible to damage from electrostatic discharge. The following precautions are essential during handling and assembly:

• Personnel should wear grounded wrist straps or anti-static gloves.
• All equipment, workstations, and storage racks must be properly grounded.
• Use an ionizer to neutralize static charges that may accumulate on the plastic lens due to friction.
• Implement an ESD training and certification program for all personnel working in the assembly area.

9. Technical Comparison & Design Considerations

Compared to older incandescent indicator lamps, this LED offers vastly superior lifetime, lower power consumption, and higher shock/vibration resistance. Within the LED family, the T-1 3/4 package provides a classic, highly visible form factor with good light output for general purpose use. Designers should note the 30-degree viewing angle, which provides a more focused beam compared to wide-angle LEDs, making it suitable for directed indication.

Key design considerations include:

• Thermal Management: Adhere to the power dissipation and current derating rules. Ensure the PCB and surrounding environment allow for adequate heat dissipation, especially in high ambient temperatures or enclosed spaces.
• Current Control: Always use a series resistor or constant current driver. Never connect the LED directly to a voltage source.
• Optical Integration: The water-clear lens produces a bright, focused spot. For diffused light, an external diffuser or light pipe may be required.

10. Frequently Asked Questions (FAQ)

Q: Can I drive this LED at 20mA continuously?

A: Yes, the maximum DC forward current is 30mA, so 20mA is within the safe operating area. Always refer to the derating curve if the ambient temperature exceeds 40°C.

Q: Why is there a ±15% tolerance on the radiant intensity bin limits?

A: This accounts for measurement system variability during production testing. It ensures that any LED falling within the declared bin, considering test tolerance, meets the performance grade.

Q: Can I use reflow soldering for this LED?

A: No. The datasheet explicitly states that IR reflow is not a suitable process for this through-hole LED. Only hand soldering or wave soldering under the specified conditions should be used.

Q: What does the 'water clear' lens mean?

A: It means the epoxy encapsulant is transparent, not diffused or tinted. This results in the highest light output and a clear view of the internal chip structure, but the light emission pattern will be more directional.

11. Practical Application Example

Scenario: Designing a panel with four status indicator LEDs for a power supply unit. The system logic voltage is 5V, and a forward current of 10mA per LED is desired for adequate brightness.

Design Steps:

1. Component Selection: Specify LTL2R3TBM3K, selecting the appropriate Ie and Vf bin based on brightness and voltage consistency requirements for the application.
2. Circuit Design: Use Circuit Model A. Assuming a worst-case VF of 3.0V (Bin 2 max), calculate the series resistor: R = (5V - 3.0V) / 0.01A = 200 Ω. A standard 200 Ω, 1/8W or 1/4W resistor would be suitable. Repeat this circuit for each of the four LEDs.
3. PCB Layout: Place the LED footprints with the specified lead spacing. Ensure the solder pads are at least 2mm away from the outline of the LED body to maintain the required soldering clearance.
4. Assembly: Follow the lead forming, soldering, and ESD guidelines meticulously during board population.

12. Operating Principle & Technology Trends

Operating Principle: This is a phosphor-converted white LED. The core is a semiconductor chip made of InGaN that emits blue light when forward biased (electroluminescence). This blue light strikes a layer of yellow (or yellow and red) phosphor coating inside the package. The phosphor absorbs a portion of the blue light and re-emits it as a broader spectrum of yellow and red light. The mixture of the remaining blue light and the phosphor-converted light is perceived by the human eye as white light.

Technology Trends: The industry continues to drive improvements in luminous efficacy (lumens per watt), color rendering index (CRI), and longevity. While surface-mount device (SMD) packages dominate new designs for miniaturization, through-hole LEDs like the T-1 3/4 remain vital for legacy designs, repair markets, hobbyist projects, and applications where robustness and ease of hand-soldering are prioritized. Advances in phosphor technology and chip design also benefit these packages, leading to brighter and more efficient devices over time.