T-1 3/4 Through Hole LED Lamp Datasheet - 572nm Yellow-Green - 20mA - 75mW - English Technical Document

1. Product Overview

This document details the specifications for a T-1 3/4 (approximately 5mm) through-hole LED lamp. The device is designed for status indication and signaling applications across a broad range of electronic equipment. It utilizes an AlInGaP (Aluminum Indium Gallium Phosphide) semiconductor chip to produce light in the yellow-green spectrum, specifically peaking at 572nm. The LED is encapsulated in a green diffused lens which helps to broaden the viewing angle and soften the light output. This type of package is a industry-standard form factor, allowing for versatile mounting on printed circuit boards (PCBs) or panels using conventional soldering techniques.

The core advantages of this LED include its compliance with RoHS (Restriction of Hazardous Substances) directives, indicating it is lead-free. It offers a balance of high luminous intensity output and low power consumption, making it suitable for both battery-powered and line-operated devices. Its design is compatible with integrated circuit (IC) drive levels, simplifying interface requirements in digital systems.

The target markets for this component are extensive, encompassing communication equipment, computer peripherals, consumer electronics, home appliances, and industrial control systems. Its primary function is to provide clear, reliable visual feedback regarding system status, power indication, or operational modes.

2. Technical Parameter Deep Dive

2.1 Absolute Maximum Ratings

These ratings define the limits beyond which permanent damage to the device may occur. They are not intended for normal operation.

• Power Dissipation (Pd): 75 mW maximum. This is the total electrical power that can be safely converted into heat and light by the LED package at an ambient temperature (TA) of 25°C.
• DC Forward Current (IF): 30 mA maximum continuous current.
• Peak Forward Current: 60 mA maximum, but only under pulsed conditions (duty cycle ≤ 1/10, pulse width ≤ 10ms). This allows for brief over-driving to achieve higher instantaneous brightness, such as in strobe or blinking applications.
• Derating: The maximum allowable DC forward current must be linearly reduced from its 30mA rating at 25°C by 0.57 mA for every degree Celsius the ambient temperature rises above 50°C. This is crucial for thermal management in high-temperature environments.
• Operating Temperature Range: -40°C to +85°C. The device is rated to function within this wide temperature span.
• Storage Temperature Range: -40°C to +100°C.
• Lead Soldering Temperature: 260°C for a maximum of 5 seconds, measured at a point 2.0mm (0.079\") from the LED body. This defines the process window for hand or wave soldering.

2.2 Electrical & Optical Characteristics

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

• Luminous Intensity (Iv): 85 to 400 mcd (millicandela), with a typical value of 180 mcd. This wide range is managed through a binning system (see Section 4). The measurement uses a sensor filtered to match the photopic (human eye) response curve (CIE). A ±15% testing tolerance is applied to the bin limits.
• Viewing Angle (2θ1/2): 40 degrees (typical). This is the full angle at which the luminous intensity drops to half of its value measured on the central axis. The green diffused lens contributes to this moderately wide viewing angle.
• Peak Emission Wavelength (λP): 575 nm (typical). This is the wavelength at the highest point in the LED's spectral output curve.
• Dominant Wavelength (λd): 566 to 578 nm. This is the single wavelength perceived by the human eye that defines the color, derived from the CIE chromaticity diagram. The target is 572nm.
• Spectral Line Half-Width (Δλ): 11 nm (typical). This indicates the spectral purity or bandwidth of the emitted light; a smaller value indicates a more monochromatic source.
• Forward Voltage (VF): 2.1 to 2.4 V (typical 2.4V) at IF=20mA. This is the voltage drop across the LED when operating.
• Reverse Current (IR): 100 μA maximum when a reverse voltage (VR) of 5V is applied. Critical Note: This test condition is for characterization only. The LED is a diode and is not designed for operation under reverse bias; applying reverse voltage can damage it.

3. Binning System Specification

To ensure consistency in production, LEDs are sorted into performance bins. This allows designers to select parts that meet specific intensity and color requirements.

3.1 Luminous Intensity Binning

Bins are defined by a code (EF0, GH0, JK0) with minimum and maximum intensity values at IF=20mA. A ±15% tolerance applies to each bin limit.

• EF0: 85 - 140 mcd
• GH0: 140 - 240 mcd
• JK0: 240 - 400 mcd

The Iv classification code is marked on each packing bag for traceability.

3.2 Dominant Wavelength Binning

Wavelength bins are defined by codes H06 through H11, each covering a 2nm range. A ±1nm tolerance applies to each bin limit.

• H06: 566.0 - 568.0 nm
• H07: 568.0 - 570.0 nm
• H08: 570.0 - 572.0 nm
• H09: 572.0 - 574.0 nm
• H10: 574.0 - 576.0 nm
• H11: 576.0 - 578.0 nm

4. Performance Curve Analysis

While specific graphical curves are referenced in the datasheet (e.g., Fig.1 for spectral peak, Fig.6 for viewing angle), the provided data allows for analysis of key relationships.

Current vs. Luminous Intensity (I-Iv Relationship): For AlInGaP LEDs, luminous intensity is generally proportional to forward current within the operating range. Driving the LED at the maximum continuous current (30mA) would yield higher intensity than the 20mA test condition, but thermal effects and efficiency droop must be considered. The pulsed current rating (60mA) allows for even higher peak brightness in duty-cycled applications.

Temperature Dependence: The derating specification (0.57 mA/°C above 50°C) is a direct indicator of thermal limitations. As junction temperature increases, the maximum allowable current decreases to prevent overheating. Furthermore, the forward voltage (VF) of an LED typically has a negative temperature coefficient, meaning it decreases slightly as temperature rises. Luminous output also generally decreases with increasing junction temperature.

Spectral Characteristics: The dominant wavelength (λd) of 572nm places this LED in the yellow-green region, which is near the peak sensitivity of the human photopic vision curve. This makes it highly efficient in terms of perceived brightness per unit of radiant power. The 11nm spectral half-width indicates a relatively narrow emission band, characteristic of AlInGaP technology, resulting in a saturated color.

5. Mechanical & Packaging Information

5.1 Outline Dimensions

The device conforms to the standard T-1 3/4 radial leaded package profile. Key dimensional notes include:

• All dimensions are in millimeters, with a general tolerance of ±0.25mm unless specified otherwise.
• The maximum protrusion of resin under the flange is 1.0mm.
• Lead spacing is measured at the point where the leads exit the package body, which is critical for PCB layout.
• The LED lead frame incorporates a cutting feature, likely for mechanical stability during assembly or as part of the manufacturing process.

5.2 Polarity Identification

For radial through-hole LEDs, the cathode (negative lead) is typically identified by a flat spot on the lens rim, a shorter lead, or a notch in the flange. The datasheet implies standard industry practice; the longer lead is usually the anode (+). Designers must verify polarity during assembly to prevent reverse connection.

5.3 Packing Specification

The LEDs are supplied in anti-static packing bags. Multiple packing options are available per bag: 1000, 500, 200, or 100 pieces. These bags are then consolidated into cartons:

• Inner Carton: Contains 15 packing bags. If using 1000-piece bags, this totals 15,000 pieces.
• Outer Carton: Contains 8 inner cartons, resulting in a total of 120,000 pieces for a full shipment using 1000-piece bags. The final pack in a shipping lot may not be full.

6. Soldering & Assembly Guidelines

6.1 Storage

For long-term storage, the ambient should not exceed 30°C or 70% relative humidity. LEDs removed from their original sealed, moisture-barrier bags should be used within three months. For extended storage outside the original packaging, they should be kept in a sealed container with desiccant or in a nitrogen-purged desiccator to prevent moisture absorption, which can cause \"popcorning\" during soldering.

6.2 Cleaning

If cleaning is necessary after soldering, only alcohol-based solvents like isopropyl alcohol (IPA) should be used. Harsh or aggressive chemicals may damage the epoxy lens.

6.3 Lead Forming

If leads need to be bent for mounting, 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 base of the LED should not be used as a fulcrum during bending, as this can stress the internal wire bonds or the epoxy seal. During PCB insertion, use minimal clinch force to avoid mechanical stress.

6.4 Soldering Process

A minimum clearance of 2mm must be maintained between the solder point and the base of the LED lens. The lens must never be immersed in solder.

• Soldering Iron: Maximum temperature 350°C, maximum time 3 seconds per lead (one-time soldering only).
• Wave Soldering: Pre-heat to a maximum of 100°C for up to 60 seconds. Solder wave temperature maximum 260°C, with a maximum immersion time of 5 seconds. The LED should be positioned so the solder wave does not come within 2mm of the lens base.
• Critical Warning: Excessive temperature or time can melt or deform the epoxy lens, degrade the internal materials, and cause catastrophic failure. Infrared (IR) reflow soldering is explicitly stated as unsuitable for this through-hole package type.

7. Application & Design Recommendations

7.1 Drive Circuit Design

An LED is a current-driven device. Its brightness is controlled by current, not voltage. To ensure uniform brightness when driving multiple LEDs, especially in parallel, it is strongly recommended to use a individual current-limiting resistor in series with each LED (Circuit Model A).

Using a single resistor for multiple LEDs in parallel (Circuit Model B) is not recommended. Small variations in the forward voltage (VF) characteristic from one LED to another will cause significant differences in the current flowing through each branch, leading to uneven brightness. The series resistor serves to stabilize the current and compensate for variations in the power supply voltage and the LED's VF.

The 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 the maximum value from the datasheet for a conservative design), and IF is the desired forward current (e.g., 20mA).

7.2 Electrostatic Discharge (ESD) Protection

The LED is susceptible to damage from electrostatic discharge. Precautions must be taken during handling and assembly:

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

7.3 Typical Application Scenarios

This LED is well-suited for both indoor and outdoor signage (where its brightness and color are effective) and general electronic equipment. Specific uses include:

• Power/Status Indicators: On/Off, standby, or operational mode lights on appliances, computers, and network equipment.
• Panel Indicators: Backlighting for switches, buttons, or legends on control panels.
• Consumer Electronics: Indicator lights on audio/video equipment, chargers, and toys.
• Industrial Controls: Status indication on machinery, sensors, and instrumentation.

8. Technical Comparison & Considerations

Compared to older technologies like GaP (Gallium Phosphide) green LEDs, this AlInGaP yellow-green LED offers significantly higher luminous efficiency and intensity, resulting in brighter output for the same drive current. The 572nm wavelength provides excellent visibility as it aligns closely with the peak sensitivity of the human eye in photopic (daylight) vision.

When selecting an LED for an application, designers must consider the trade-offs between viewing angle and axial intensity. This LED's 40-degree viewing angle offers a good compromise, providing a reasonably wide viewing cone while maintaining good on-axis brightness. For applications requiring an extremely wide viewing angle, a different lens shape (e.g., a flat-top or side-view package) would be more appropriate.

The through-hole package offers advantages in prototyping, manual assembly, and applications requiring high mechanical strength of the solder joint. However, for high-volume automated assembly, surface-mount device (SMD) packages are generally preferred due to faster placement speeds and reduced board space.

9. Frequently Asked Questions (Based on Technical Parameters)

Q: Can I drive this LED directly from a 5V digital logic output?
A: No. The typical forward voltage is 2.4V. Connecting it directly to 5V would cause excessive current to flow, destroying the LED. You must use a series current-limiting resistor. For a 5V supply and a target of 20mA, a resistor of approximately (5V - 2.4V) / 0.02A = 130 Ohms would be a starting point (use the nearest standard value, e.g., 120 or 150 Ohms).

Q: What does the \"derating\" specification mean for my design?
A: If your application operates in an ambient temperature above 50°C, you must reduce the maximum continuous current. For example, at 70°C ambient (20°C above the 50°C reference), you must reduce the current by 20°C * 0.57 mA/°C = 11.4 mA. Therefore, the maximum safe continuous current at 70°C would be 30 mA - 11.4 mA = 18.6 mA.

Q: Why is there a separate \"peak\" current rating?
A: The LED can handle higher current in short pulses because the heat generated does not have time to raise the junction temperature to a damaging level. This is useful for creating very bright flashes or for multiplexing schemes where multiple LEDs are driven in sequence.

Q: How do I interpret the binning codes when ordering?
A: You would specify the desired luminous intensity bin (e.g., GH0 for 140-240 mcd) and dominant wavelength bin (e.g., H08 for 570-572nm) to ensure the LEDs you receive have consistent brightness and color. If your application is not color-critical, a wider wavelength bin may be acceptable and potentially more cost-effective.

10. Design-in Case Study Example

Scenario: Designing a status indicator panel for an industrial controller that operates in an environment up to 60°C. The panel has three LEDs: Power (steady on), Fault (blinking), and Active (pulsing during communication). The system uses a 3.3V microcontroller for control.

Design Steps:

1. Current Selection: Due to the 60°C ambient, apply derating. Temperature above 50°C is 10°C. Current reduction = 10°C * 0.57 mA/°C = 5.7 mA. Maximum continuous current = 30 mA - 5.7 mA = 24.3 mA. A design target of 15mA is chosen for reliability and longevity, providing good brightness while staying well within limits.
2. Resistor Calculation: Using Vcc = 3.3V, VF(max) = 2.4V, IF = 15mA. R = (3.3V - 2.4V) / 0.015A = 60 Ohms. A standard 62-ohm resistor is selected.
3. Drive Method: Each LED is connected between a microcontroller GPIO pin (configured as an output) and ground, with its own 62-ohm series resistor. The \"Fault\" LED is blinked by software. The \"Active\" LED is pulsed at a higher frequency for a distinct visual effect, staying within the 1/10 duty cycle limit if using pulses above 30mA.
4. Binning: For consistent appearance, specify the GH0 intensity bin and the H08 or H09 wavelength bin to ensure all three LEDs match closely in brightness and hue.
5. Layout: PCB holes are placed according to the lead spacing dimension. A keep-out area of at least 2mm radius around the LED body is maintained to prevent solder wicking during wave soldering.

11. Technology Principle Introduction

This LED is based on AlInGaP semiconductor material grown on a substrate. When a forward voltage is applied across the p-n junction, electrons and holes are injected into the active region where they recombine. This recombination process releases energy in the form of photons (light). The specific wavelength of the light (color) is determined by the bandgap energy of the semiconductor material, which is engineered by adjusting the ratios of Aluminum, Indium, Gallium, and Phosphorus during crystal growth. The 572nm yellow-green emission is achieved with a specific composition of AlInGaP. The green diffused epoxy lens serves multiple purposes: it encapsulates and protects the fragile semiconductor chip and wire bonds, acts as a refractive element to shape the light output beam (creating the 40-degree viewing angle), and contains diffusant particles to scatter the light, making the emitting surface appear more uniform and less glaring.

12. Industry Trends & Context

While through-hole LEDs like this T-1 3/4 package remain vital for repair, hobbyist, and certain industrial markets, the dominant trend in electronics manufacturing is towards surface-mount technology (SMT). SMD LEDs offer significant advantages in automated assembly speed, board space savings, and lower profile. However, through-hole components are valued for their mechanical robustness, ease of manual soldering and rework, and superior thermal connection to the PCB via the leads. In terms of material technology, AlInGaP remains the standard for high-efficiency red, orange, amber, and yellow-green LEDs. For true green and blue colors, InGaN (Indium Gallium Nitride) is the prevalent technology. The development focus continues to be on increasing luminous efficacy (lumens per watt), improving color consistency and stability over temperature and lifetime, and enhancing reliability under harsh environmental conditions.