LTL1CHVRTNN Red LED Lamp Datasheet - T-1 Package - 2.4V - 75mW - English Technical Document

1. Product Overview

The LTL1CHVRTNN is a high-efficiency, low-power consumption through-hole LED lamp designed for status indication and illumination in a wide range of electronic applications. It features a popular T-1 (3mm) diameter package with a red transparent lens, offering a balance of brightness and viewing angle suitable for diverse design requirements.

1.1 Core Advantages

• High Efficiency & Low Power Consumption: Delivers high luminous intensity with minimal power draw, making it ideal for battery-powered or energy-conscious applications.
• RoHS Compliance & Lead-Free: Manufactured in accordance with environmental regulations, ensuring suitability for modern global markets.
• Standard Package: The T-1 (3mm) form factor is widely used and compatible with standard PCB layouts and mounting hardware.
• Design Flexibility: Available in specific bins for luminous intensity and dominant wavelength, allowing for consistency in color and brightness across production runs.

1.2 Target Markets

This LED is versatile and targets multiple industries including:

• Communication Equipment
• Computer Peripherals
• Consumer Electronics
• Home Appliances
• Industrial Control Systems

2. In-Depth Technical Parameter Analysis

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): 75 mW. This is the maximum power the LED can dissipate as heat at an ambient temperature (TA) of 25°C. Exceeding this limit risks thermal damage.
• DC Forward Current (IF): 30 mA. The maximum continuous current that can be applied.
• Peak Forward Current: 90 mA (pulse width ≤10μs, duty cycle ≤1/10). Suitable for brief, high-intensity pulses but not for continuous operation.
• Operating Temperature Range: -40°C to +85°C. The device is rated to function within this ambient temperature span.
• Lead Soldering Temperature: 260°C for a maximum of 5 seconds at a distance of 2.0mm from the LED body. Critical for wave or hand soldering processes.

2.2 Electrical & Optical Characteristics

These are the typical performance parameters measured at TA=25°C and IF=20mA, the standard test condition.

• Luminous Intensity (Iv): 1500 - 3200 mcd (millicandela). This high brightness level ensures excellent visibility. The actual value is binned (R, S, T) for consistency.
• Viewing Angle (2θ1/2): 45 degrees. This defines the cone within which the luminous intensity is at least half of the on-axis intensity. It offers a good compromise between focused beam and wide visibility.
• Peak Emission Wavelength (λP): 639 nm. The wavelength at which the spectral power output is maximum.
• Dominant Wavelength (λd): 621 - 637 nm. This is the single wavelength perceived by the human eye, defining the color (red). It is binned (H29-H32) for precise color matching.
• Forward Voltage (VF): 2.0V (Min), 2.4V (Typ). The voltage drop across the LED when driven at 20mA. This parameter is crucial for designing the current-limiting resistor in the drive circuit.
• Reverse Current (IR): 100 μA (Max) at VR=5V. The LED is not designed for reverse bias operation; this parameter is for leakage current testing only.

3. Binning System Explanation

To ensure product consistency, the LEDs are sorted into bins based on key optical parameters.

3.1 Luminous Intensity Binning

Binning guarantees a minimum brightness level. Tolerance for each bin limit is ±15%.

• Bin R: 1500 - 1900 mcd
• Bin S: 1900 - 2500 mcd
• Bin T: 2500 - 3200 mcd

3.2 Dominant Wavelength Binning

Binning ensures precise color consistency. Tolerance for each bin limit is ±1nm.

• Bin H29: 621.0 - 625.0 nm
• Bin H30: 625.0 - 629.0 nm
• Bin H31: 629.0 - 633.0 nm
• Bin H32: 633.0 - 637.0 nm

4. Performance Curve Analysis

While specific graphs are referenced in the datasheet, their implications are critical for design.

4.1 Forward Current vs. Forward Voltage (I-V Curve)

The I-V characteristic is non-linear. A small increase in voltage beyond the typical VF can cause a large, potentially damaging increase in current. This underscores the necessity of using a constant current source or, more commonly, a current-limiting resistor in series with the LED.

4.2 Luminous Intensity vs. Forward Current

Luminous intensity is approximately proportional to forward current up to the maximum rated current. However, efficiency may drop at very high currents, and excessive heat will be generated. Operating at or below the recommended 20mA ensures optimal performance and longevity.

4.3 Spectral Distribution

The spectral curve shows a narrow half-width (Δλ of 20 nm typical), indicating a relatively pure red color. The peak (639 nm) and dominant (621-637 nm) wavelengths define its specific shade within the red spectrum.

5. Mechanical & Packaging Information

5.1 Outline Dimensions

The LED conforms to the standard T-1 (3mm) radial leaded package. Key dimensional notes include:

• All dimensions are in millimeters.
• Tolerance is ±0.25mm unless specified.
• Maximum resin protrusion under the flange is 1.0mm.
• Lead spacing is measured where leads exit the package body.

5.2 Polarity Identification

The longer lead is the anode (+), and the shorter lead is the cathode (-). The cathode side may also be indicated by a flat spot on the lens flange. Correct polarity must be observed during circuit assembly.

6. Soldering & Assembly Guidelines

6.1 Storage Conditions

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 storage, use a sealed container with desiccant or a nitrogen ambient.

6.2 Lead Forming

Bend leads at a point at least 3mm from the base of the LED lens. Do not use the lens base as a fulcrum. Forming must be done before soldering and at room temperature to avoid stress on the internal die bonds.

6.3 Soldering Process

Critical Rule: Maintain a minimum distance of 2mm from the base of the epoxy lens to the solder point. Do not immerse the lens in solder.

• Soldering Iron: Max temperature 350°C, max time 3 seconds per lead.
• Wave Soldering: Pre-heat ≤100°C for ≤60 sec, solder wave ≤260°C for ≤5 sec.
• Important: IR reflow soldering is NOT suitable for this through-hole LED type. Excessive heat or time will deform the lens or cause catastrophic failure.

7. Packaging & Ordering Information

7.1 Packaging Specification

The LEDs are packed in anti-static bags to prevent ESD damage.

• Bag Quantities: 1000, 500, 200, or 100 pieces per bag.
• Inner Carton: 10 bags per carton (total 10,000 pcs).
• Outer Carton: 8 inner cartons per outer carton (total 80,000 pcs).

8. Application Design Recommendations

8.1 Drive Circuit Design

LEDs are current-operated devices. To ensure uniform brightness, especially when connecting multiple LEDs in parallel, a series current-limiting resistor for each LED is mandatory (Circuit A). Avoid connecting LEDs directly in parallel without individual resistors (Circuit B), as slight variations in their forward voltage (VF) will cause significant current imbalance and uneven brightness.

Resistor Calculation Example (for a 5V supply, target IF=20mA, VF=2.4V):
R = (Vsupply - VF) / IF = (5V - 2.4V) / 0.020A = 130 Ω.
Nearest standard value (e.g., 120 Ω or 150 Ω) can be used, recalculating the actual current.

8.2 ESD (Electrostatic Discharge) Protection

LEDs are sensitive to static electricity. Preventive measures are essential during handling and assembly:

• Use grounded wrist straps and anti-static mats.
• Ensure all equipment and work surfaces are properly grounded.
• Use ionizers to neutralize static charge on plastic lens surfaces.
• Implement ESD training and certification for personnel.

8.3 Thermal Management

While the power dissipation is low (75mW max), maintaining the LED within its operating temperature range (-40°C to +85°C ambient) is important for long-term reliability. Avoid placing the LED near other heat-generating components. In high-density layouts, ensure adequate airflow.

9. Technical Comparison & Differentiation

The LTL1CHVRTNN differentiates itself within the T-1 red LED category through its specific combination of high luminous intensity (up to 3200 mcd) and a standard 45-degree viewing angle. Compared to generic parts, its defined binning structure for both intensity and wavelength provides designers with predictable performance, reducing the need for post-production calibration in applications where color and brightness consistency are critical, such as in indicator arrays or backlighting panels.

10. Frequently Asked Questions (FAQs)

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

No. Connecting it directly to a voltage source will cause excessive current flow, instantly damaging the LED. A series resistor or constant current driver is always required.

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

Peak Wavelength (λP) is the physical wavelength where the LED emits the most optical power. Dominant Wavelength (λd) is a calculated value based on human eye sensitivity (CIE curve) that defines the perceived color. λd is more relevant for visual applications.

10.3 Can I use reflow soldering for this LED?

No. The datasheet explicitly states that IR reflow is not suitable for this through-hole type LED lamp. Only wave soldering or hand soldering with careful temperature and time control is recommended.

10.4 How do I interpret the bin code on the packing bag?

The bin code (e.g., T-H31) indicates the luminous intensity bin (T: 2500-3200 mcd) and the dominant wavelength bin (H31: 629.0-633.0 nm). This allows you to select LEDs with matched performance for your application.

11. Practical Application Example

Scenario: Designing a status indicator panel for industrial equipment requiring 10 uniformly bright red LEDs.

1. Component Selection: Specify LTL1CHVRTNN LEDs from the same intensity bin (e.g., Bin S) and wavelength bin (e.g., Bin H31) to guarantee visual consistency.
2. Circuit Design: Use a 12V DC power rail. Calculate the series resistor for each LED: R = (12V - 2.4V) / 0.020A = 480 Ω. A 470 Ω, 1/4W resistor is suitable. Connect all 10 LED-resistor pairs in parallel to the 12V rail.
3. PCB Layout: Place holes for the 3mm LED body. Ensure the pad for the cathode (shorter lead) is clearly marked. Maintain >2mm clearance between the solder pad and the LED body outline.
4. Assembly: Follow ESD precautions. Insert LEDs, bend leads slightly on the solder side to hold them in place. Use wave soldering with parameters not exceeding 260°C for 5 seconds.

12. Operating Principle

This LED is a semiconductor p-n junction diode. When a forward voltage exceeding its characteristic forward voltage (VF ~2.4V) is applied, electrons and holes recombine at the junction, releasing energy in the form of photons (light). The specific materials used in the semiconductor layers determine the wavelength (color) of the emitted light, which in this case is in the red spectrum (621-637 nm). The epoxy lens serves to focus the light output and protect the semiconductor die.

13. Technology Trends

While surface-mount device (SMD) LEDs dominate new designs for miniaturization and automated assembly, through-hole LEDs like the T-1 package remain relevant in specific niches. Their demand persists in applications requiring high reliability in harsh environments (vibration, thermal cycling), easier manual prototyping and repair, legacy system maintenance, and situations where the component itself acts as a panel-mounted indicator protruding through an enclosure. The technology continues to improve in terms of luminous efficacy (more light output per watt) and color consistency, even within the established through-hole form factors.